Description : The average speed of a train is 1 3/7 times the average speed of a car. The car covers a distance of 616 km in 8 hours. How much distance will the train cover in 13 hours? a) 1340 km b) 1423 km c) 1430 km d) 1936 km e) None of these
Last Answer : speed of the car = 616/8 = 77km/hr speed of the train = 10/7 × 77 = 110 km/hr Distance covered by train = 110 × 13 = 1430 km. Answer: c)
Description : A shatabadi express takes 240 seconds to cover a distance of length 700 meters at a speed of 270 km/hr. What will be the time taken by the train to cross a standing pole? A) 160sec B) 465sec C) 310sec D) 231sec
Last Answer : ANSWER:D Explanation: Speed of the train = 270 km/hr. Converting the speed into m/sec Speed = 270 km/hr = 270 x 5/18 m/sec = 75 m/sec First, we have to find the length of the train Let ... a standing Pole at 75 m/s =( 17300/75)seconds = 231 seconds. Hence the answer is 231 sec(approx.)
Description : It takes eight hours for a 600 km journey, if 120 km is done by train and the rest by car. It takes 20 minutes more, if 200 km is done by train and the rest by car. The ratio of the speed of the train to that of the cars is? a) 2 : 3 b) 3: 2 c) 3 : 4 d) 4 : 3 e) None of these
Last Answer : Let the speed of the train be x km/hr and that of the car be y km/hr. Then, 120/x+480/y= 8 1/x+4/y=1/15 ....(i) And, 200/x+400/y=25/3 1/x+2/y=1/24 ....(ii) Solving (i) and (ii), we get: x = 60 and y = 80. Ratio of speeds = 60 : 80 = 3 : 4. Answer: c)
Description : A train covers the first half of the distance between two stations with a speed of 40 km/h and the other half with 60 km/h. Then its average speed is
Last Answer : A train covers the first half of the distance between two stations with a speed of 40 km/h and the other half with ... 48 km/h C. 52 km/h D. 100 km/h
Description : A train accelerates from 36 km/h to 54 km/h in 10 sec. (i) Acceleration (ii) The distance travelled by car. -Science
Last Answer : a. Acceleration is given by a=ΔvΔta=ΔvΔt Δv=54−36=18km/hr=18×10003600m/s=5m/sΔv=54−36=18km/hr=18×10003600m/s=5m/s So a=.5 m/s2 b. Distance is given by S=ut+12at2S=ut+12at2 Now u=36 km/hr =10m/s s=10×10+12×.5×102s=10×10+12×.5×102 So s=125m
Description : A 250 m goods train takes 50 s to cross a person who is going in the same direction with the speed of 8 km/h. After crossing that person, the train can reach next station in 2 hr. How long that person takes to reach that station after being crossed by them? A) 2 ½ hr B) 5hr C) 3 1/2hr D) 1hr
Last Answer : ANSWER:A Explanation: Speed of the person = 8 kmph = (8*5/18)m/s = 20/9 m/s Then relative speed of train = (x-20/9)m/s As train takes 50 sec to cross the person Therefore 50 =250/(x-20/ ... 20,000 m = 20 km Thus time taken by the person to cover the distance of 20km= 20/8 hr=2 ½ hr
Description : A pedal boat can cover 20km in 1 hr in still water. And it takes thrice as much as time to cover up than as to cover down the same distance in running water. The speed of the current is. A) 7.5 km/hr B) 20 km/hr C) 5 km/hr D) 10 km/hr
Last Answer : ANSWER : D Explanation: Let the speed of upstream be x' km/hr Then speed in downstream = 3x km/hr[thrice as much as time to cover up than as to cover down the same distance in running water] Speed in ... Speed in downstream = 30 km/hr Hence speed of the current = (30 -10)/2 = 10 km/hr.
Description : Anand takes 9 hours more than Babu to cover 150 km. Suppose the time taken by Anand is 30 minutes less than Babu he must double his speed. Then the speed of Anand will be: a) 7.64 km/hr. b) 7.43km/hr. c) 7.89 km/hr. d) 7.25 km/hr.
Last Answer : C Let Anand 's speed be X km/hr. And let the time taken by Babu be Y. Since Anand takes 9+Y hours to cross 150km at X km/hr. i.e., 150 / X = 9+Y ---eqn1 And he takes Y - 1/2 hours to cross 150km at 2X km ... )/ 2x = 19/2 150/2X =19/2 150/X = 19 X = 7.89 Hence Anand 's speed is 7.89 km/hr.
Description : A boat takes 24 hours to cover 128 km downstream and 16 hours to cover 64 km upstream. Then the speed of the boat in still water is: A) 14/3 B) 8/7 C) 3/2 D) 9/5
Last Answer : Answer: A Explanation: Distance covered in downstream = 128km Time taken in downstream = 24 hours. Rate of downstream = distance / time = a = 128 km /24 hours = 16/3km/hr Distance covered in upstream = 64km Time taken in upstream ... / 2 = (1/2)(16/3+4) km/hr = (1/2)(28/3)km/hr = 14/3km/hr.
Description : A boat running downstream covers a distance of 20 km in 5 hours while for covering the same distance upstream, it takes 10 hours. What is the speed of the stream? a) 2km/hr b) 4km/hr c) 1km/hr d) 1.5 km/hr e) None of these
Last Answer : c Rate of downstream=(20 / 5 ) kmph= 4kmph Rate of upstream =( 20/10) kmph= 2kmph Therefore Speed of the stream= (1/2)(4 - 2) kmph= 1 kmph
Description : The distance between two stations ooty and chennai is 615km. A train with speed of 75 km/h leaves ooty at 8:00 am towards chennai. Another train with speed of 105 km/h leaves Chennai at 9 : 00 am towards ooty . Then, at what time both trains meet? A) 6 B) 12 C) 18 D) 24
Last Answer : ANSWER:B Explanation: First train leaves at 8.00am and second leaves at 9.00am So,first train that is , from ooty to Chennai has covered 75 km distance in 1 hr. So , distance left by between the station = ... the trains will meet , 3 hr after second train left i.e., 9.00 am +3 = 12.00 pm
Description : A man takes 10 hours to cover a distance while traveling upstream on a boat, whereas while traveling downstream it takes 6 hours. If the speed of the boat in still water is 6 kmph, what is the speed of the stream? 1 : 2.5 kmph 2 : 2.2 kmph 3 : 2 kmph 4 : 1.5 kmph 5 : None of these
Last Answer : 4 : 1.5 kmph
Description : A 1800 km journey of 24 hrs, if 360km is done by van and the rest by train. It takes 60 mins more, if 600km is done by van and the rest by train. The ratio of the speed of the van to that of the train is. a) 2:4 b) 4:3 c) 3:4 d) 5:3
Last Answer : C Let the speed of the van be x km/hr And that of the train be y km/hr 360/x+1440/y = 24 --------------->A Dividing by 24 on both sides 15/x+60/y = 1 ---------1 And 600/x +1200/y =25 Dividing by ... 720/y =9 Y=80 Put y value in A 360/x = 24-18 X=360/6 X=60 Ratio of speeds = 60:80 = 3:4
Description : A passenger train without stopping running at an average speed of 120 km/hr and with stoppages at an average speed of 80 km/hr. What is the total time taken by the train for stoppages on a route of length 480km? a) 2 hours b) 3 hours c) 4 hours d) 5 hours
Last Answer : A Let r = running time of the train s= stoppage time of the train D= total distance travelled by train We have: D/r= 120 and ..(1) D/(r+s) =80 ..(2) Diviving (1)&(2), D/r *(r+s)/D = ... , D=480 kms 480/r= 120 r=4 put r value in (3),we get s/4 =1/2 S = 2 hours
Description : In covering a distance of 30 km, Abhay takes 2 hours more than Sameer. If Abhay doubles his speed, then he would take 1 hour less than Sameer. Abhay's speed is? a) 5 kmph b) 6 kmph c) 6.25 kmph d) 7.5 kmph e) None of these
Last Answer : Let Abhay's speed be x km/hr. Then, 30/x-30/2x= 3 6x = 30 x = 5 km/hr. Answer: a)
Description : Anitha travels 400 km by bus at 70 km/hr, 600 km by train at 80km/hr, 250 km by bike at 60 km/hr and 50 kn by car at 40 km/hr. what is the average speed for the total distance? a) 68.45 b) 69.45 c) 67.45 d) 69.77
Last Answer : D Total distance = (400+250+50+600)km =1300 km Total time taken = (400/70 + 600/80+250/60+50/40) hrs =(40/7 +60/8+25/6+5/4) =(24*40)+(21*60)+(28*25)+(42*5) / 168 =960+1260+700+210 / 168 =(3130 / 168) Average speed =(1300*168 / 3130) km/hr =218400/3130 =69.77 km/hr
Description : Distance between two stations P & Q is 1556km. A passenger train covers the journey from P to Q at 168km per hr and return back to P with a uniform speed of 112km/hr. Find the Average speed of the train during the whole journey? A) 124.4 km/hr B) 130.4km/hr C) 134.4 km/hr D) 130.0 km/hr
Last Answer : C) Given x= 168 , y = 112 Required average speed = (2xy / x + y) km/hr = 2 * 168 *112 / 168 + 112 = 37632 / 280 =134.4 km/hr
Description : A person runs on the platform of 90 m at a speed of 5km/hr in the same direction of the passenger train. Find the time taken by the train to cross the running person if speed of the train is 35.5 km/hr? (Length of train = Length of platform) A) 5.32sec B) 7.5sec C) 12.6sec D) 10.62sec
Last Answer : ANSWER:D Explanation: speed of the train = 35.5 km/hr speed of the person = 5 km/hr As the train and the running person move in same direction, their speed values are subtracted to find the relative ... =10.62 sec Hence, the time taken by the train to cross the running person is 10.62 sec
Description : Shreya travel the first part of her journey at 160 kmph and the second part at 240 kmph and cover the total distance of 3840 km to her destination in 20 hours. How long did the first part of her journey last? a) 8 hrs b) 12 hrs c) 16 hrs d) 10 hrs
Last Answer : B The total time of journey = 20 hours. Let 'x' hours be the time that shreya travelled at 160 kmph Therefore, 20-x hours would be time that she travelled at 240 kmph. Hence, she would have covered x*160+( ... 20-x)*240 =3840 160x +4800-240x =3840 240x-160x=4800-3840 80x= 960 X=960/80=12 hrs
Description : A metro train 200 metres long takes 12 seconds to cross a man walking at 10 km/hr in a opposite to that of the train. Find the speed of the train? A) 50 km/hr B) 60km/hr C) 130km/hr D) 140km/hr
Last Answer : ANSWER: A Explanation: Length of the train = 200 m Man walking speed = 10 km/hr Let the speed of the train be x' km/hr Speed of the train relative to man = (x +10) km/hr Convert km/hr into m/s ... = 60(x +10) 3600 = 60x +600 60x = 3000 X = 50 So speed of the train is 110km/hr.
Description : Two cars A and B race each other. The Car A ran for 2 minute at a speed of 7.5 km/h, slept for 56 minute and again ran for 2 minute at a speed of 7.5 km/h. find the average speed of the car A in the race. -Science
Last Answer : We know that Distance=speed×timeDistance=speed×time Distance travelled in first 2 minute = 7.5×2607.5×260 = 0.25 km Distance travelled in last 2 minute = 7.5×2607.5×260= 0.25 km Total distance = .25+.25 = 0.5 km Total time = 2+2+56 = 60 minute = 1 hr Average speed = 0.5/1 = 0.5 km/hr
Description : A train leaves Mumbai for chennai at 6 : 45 a.m. and goes at the rate of 100 km/h. Another train leaves Chennai for Mumbai at 4.30a.m. and goes at the rate of 120 km/h. If the distance between both is 1240 km, at what distance from Mumbai will the two trains meet? A) 210km B) 324km C) 115km D) 440km
Last Answer : ANSWER: D Explanation: Given speed of the first train = 100kmph speed of the second train = 120kmph The second train leaving Chennai starts its journey earlier and it travels = 120 *(6.45a.m. ... train covers 4.40 *100 = 440 km Therefore the first train meet to the second train at 440km
Description : A train 100 m long is moving with the velocity of 72 km/hr. Find the time it takes to cross the bridge which is 2 km long? -Science
Last Answer : Given Lenght of Train = 100m , velocity = 72 km/hr = 20 m/s, Lenght of the Bridge =2 Km. Total distance covered by the train to fully pass the bridge = 2000 + 100 = 2100 m So, time taken time=distancevelocity=210020=105sectime=distancevelocity=210020=105sec
Description : Length of train is 510 meters and speed of train is 63 km/hour. This train can pass a pole in 90 seconds, then find the length of the pole? A) 575mts B) 2500mts C) 1065mts D) 876mts
Last Answer : ANSWER: C Explanation: Given speed of the train = 63 km/hr = 63*5/18 m/s =17.5m/s Let the length of the pole = x mts Given time taken to cover the distance of (510+ x)mts is 90 sec. We know speed = ... m/s 17. 5 = 510+x/90 1575 = 510+x x = 1065 Therefore the length of the pole is 1065 mts
Description : A motor car starts with the speed of 70 km/hr with its speed increasing every two hours by 10 kmph. In how many hours will it cover 345 kms? A.4 hrs B.4 hrs 5 mins C.4 1/2 hrs D.2 hrs E.None of these
Last Answer : Answer - C (4 1/2 hrs) Explanation - Distance covered in first 2 hours = (70 x 2) km = 140 km Distance covered in next 2 hours = (80 x 2) km = 160 km Remaining distance = 345 - (140 + 160) = 45 km. Speed in the ... ..1 hr 45km .? ?=45/90hr=1/2hr Total time taken = 2 + 2 +1/2=4 (1/2)hrs
Description : A train starts from Delhi and reaches Lucknow in 24.5 hours. If it travels the first half of journey at 30 kmph and second half at 40 kmph then what is the total distance it travelled? 1) 750 km 2) 800 km 3) 840 km 4) 900 km 5) 920 km
Last Answer : 3) 840 km
Description : Raghu starts a bike at 40 km/hr and he increases his speed in every hour by 4 km/hr. Then the maximum distance covered by him in 12 hours is: a) 744 km b) 658 km c) 436 km d) 512 km
Last Answer : A Speed of the rider = 40km/hr. Distance covered in 1st hour = 40 km. He increased his speed in every 1 hour by 4 km/hr. Distance covered in every 1 hours will be, 44, 48, ,... upto 12 terms.(for 12 hours). ... (2(40)+(11)4) = 6(80 + 44) = 6(124) = 744. Hence, he covers 744 km in 12 hours.
Description : A motorboat running upstream takes 4 hrs 24 mins to cover a certain distance, while it takes 2hrs to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively? A) 8:3 B) 5:2 C) 3:7 D) 2:4
Last Answer : ANSWER : A Explanation: Let the man's rate upstream be x'km/hr and downstream be y'km/hr Then distance covered upstream by 4hrs 24mints = distance covered by downstream in 2hrs (x * 4 2/5) = y *2 22x/5 = 2y Y = ... = (y+x/2) : (y -x/2) = 16x/10 : 6x/10 = 16x : 6x = 8:3
Description : A boy sitting in a train which is travelling at 25 km/hr observes that a goods train travelling in opposite direction, takes 4.5 seconds to pass him. If the train is 140 m long, find its speed. A) 77km/hr B) 79km/hr C) 87km/hr D) 89km/hr
Last Answer : ANSWER : C Explanation: Relative speed = distance / time = (140 / 4.5) m/s = 31.11 m/s Convert m/s into km/hr 31.11 m/s = (31.11 * 18 / 50 km/hr = (560 / 5) km/hr = ... train (by sitting) = (112 - 25) km/hr = 87 km/hr Therefore the speed of goods train is 87 km/hr.
Description : It takes 60 sec for a train running at 162 km/hr to cross a bridge. And it takes 36 sec for the same speed to cross a boy walking at the rate of 18km/hr in the same direction in which the train is ... the train and length of the platform. A) 1440 &1260m B) 1220 &60m C) 1000 & 1460m D) 1260 &1450m
Last Answer : ANSWER: A Explanation: Relative speed of the train to man = (162 - 18) = 144km/hr Convert km/hr into m/s 144km/hr = (144 * 5 /18) m/s = 40 m/s When the train passes ... of bridge = 2700 length of bridge = 1260 m the length of the bridge & train are 1260 and 1440m
Description : A goodstrain of 700 m runs at a speed of 165 km/hr. A person traveling in it observes that the mail train moving in opposite direction takes 30 seconds to cross him. Find the speed of the mail train, if it is 750 m long. A) 8.4 m/s B) 5.3 m/s C) 2.5 m/s D) 6.8 m/s
Last Answer : ANSWER:C Explanation: Speed of goods train = 165km/hr length of mail train (P) = 750m length of goods train (Q) = 700m Alternately, we can directly use the formula: Time = ( p+q) / (v1+v2) sec ( ... 45.833+v2 = 48.333 V2 = 2.5 m/s Therefore the speed of the mail train is 2.5 m/s
Description : A train 135m long is moving at a speed of 12.5 km/h. It will cross a girl coming from the opposite direction at a speed of 1km/hr in. A) 36sec B) 46sec C) 56sec D) 66sec
Last Answer : ANSWER : A Explanation: Speed of the train = 12.5 km/hr Speed of girl = 1 km/hr Relative speed = speed of train + speed of girl = (12.5 + 1) km/hr = 13.5 km/hr Convert km/hr into m/s 13.5 ... .75 m/s Time = distance / speed Time taken by the train to pass the man = 135 / 3.75 = 36 sec.
Description : A train, travelling at a uniform speed for 360 km, would have taken 48 minutes less to travel the same distance if its speed were 5 km/hr more. Find the original speed of the train. -Maths 10th
Last Answer : Let the speed of train be x km/hr Distance to be travelled = 360km We know that, Time take by the train intially = If the speed was increased by 5km/hr Time taken by train = Difference in the time taken is 48 minutes, x2+5x -2250 = 0 (x+50)(x-45) Speed = 45 km/hr as speed cannot be negative
Description : Two trains are moving in opposite directions at 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is: A.58 sec B.50 sec C.48 sec D.56 sec E.None of these
Last Answer : Answer – C (48 sec) Explanation – Relative speed = all lengths/time [60+90] = [1.10 +0.9 ]/time [ PLUS when opposite direction] time=2/150 = 1/75 h 1 hour______3600 sec 1/75 hr______? ?= 3600/75=48 sec
Description : A motorboat can cover 80 km upstream and 120 km downstream together in 26 hours. Also it can cover 100 km upstream and 144 km downstream together in 32 hours. What is the speed of the motorboat in still water? A) 12 km/hr B) 15km/hr C) 8.5km/hr D) 19km/hr
Last Answer : ANSWER :C Explanation: Upstream speed in both cases is 80 and 100. Ratio is 80 : 100 = 8:10 = 4 : 5. So let times in both cases be 4x and 5x Downstream speed in both cases is 120 and 144 resp. Ratio is ... 12 km/hr So speed of boat = 1/2 * (5+12) =17/2km/hr speed of boat = 8.5 km/hr
Description : Speed of a boat in standing water is 9kmph and the speed of the stream is 1.5kmph. A man rows to a place at a distance of 10.5 km and comes back to the starting point. Find the total time taken by him. A.24 hours B.16 hours C.20 hours D.15 hours
Last Answer : Answer- A Basic Formula: i. speed = distance traveled / time taken ii. speed of the stream = ½ (a-b) km/hr iii. speed in still water = ½ (a+b) km/hr Explanation: Speed in still water= ½ (a+b) = 9km ... gives a = 10.5km/hr ; b=7.5 kmphr Total time taken by him = 105/10.5 + 105/7.5 = 24 hours
Description : If the velocity of moving vehicles on a road is 24 km/per hour, stopping distance is 19 metres and average length of vehicles is 6 metres, the basic capacity of lane, is (A) 500 vehicles per hour (B) 700 vehicles per hour (C) 1000 vehicles per hour (D) 1250 vehicles per hour
Last Answer : Answer: Option C
Description : Pick up the incorrect statement from the following: (A) Lead is the average horizontal straight distance between the borrow pit and the place of spreading soil (B) The lead is calculated for each block of the ... a distance upto 500 m (D) The unit of lead is 1 km where the lead exceeds 2 km
Last Answer : (D) The unit of lead is 1 km where the lead exceeds 2 km
Description : A diver rowing at the rate of 5 km/h in still water takes double the time in going 40 km upstream as in going 40 km downstream. Find the speed of the stream. -Maths 10th
Last Answer : 5/3 km/h Step-by-step explanation: Speed in still water = 5km/h Define x: Let the speed of the steam be x Upstream speed = (5 - x) km/h Downstream speed = (5 + x) km/h Time taken going upstream: Time taken = ... 40x = 400 - 80x 120x = 200 x = 200 120 = 5/3 The speed of the stream is 5/3 km/h
Description : A motor boat whose speed is 18 km/h in still water takes 1 hour more to go 24 km upstream than to return downstream to the same spot. Find the speed of the stream. -Maths 10th
Last Answer : The given speed of the motor boat in the still water is equal to 18 km/ hr. The given distance travelled by motor boat is equal to 24 km. The time taken to travel 24 km downstream by motor boat = 1 hour. x=122=6 km/ hr.
Description : Determine the maximum length of the cable (in km) for transmitting data at a rate of 500 Mbps in an Ethernet LAN with frames of size 10,000 bits. Assume the signal speed in the cable to be 2,00,000 km/s. b. 2 c. 2.5 d. 5
Last Answer : b. 2
Description : Tharun has to cover a distance of 84 km in 40 minutes. If he covers one-half of the distance in one-fourth of the total time, to cover the remaining distance in the remaining time, what should be his speed in km/hr? a) 42 km/hr b) 64km/hr c) 84km/hr d)76km/hr
Last Answer : C Tharun needs to cover 84 km in 40minutes Given that he covers one-half of the distance in one-fourth of the total time ⇒ he covers half of 84km in one-fourth of 40 minutes ⇒ He covers 42 km in ¼ * ... Distance =42km Time =30minutes =1/2 hr Required Speed = Distance / Time =42/(1/2)=84 km/hr
Description : A motor boat sails 30 km of a river towards upstream in 10hrs. How long will it take to cover the same distance downstream, if the speed of the current is ½ of the speed of the boat in still water. A) 1.8hrs B) 3.33hrs C) 5hrs D) None of these
Last Answer : ANSWER : B Explanation: Upstream speed = x –y Downstream speed = x + y x– y = 30/10 = 3km/hr Again x = 2y Therefore x – y = 3 y= 3km/hr ; x = 6km/hr Therefore x + y = 9 km/hr Time during downstream = 30/9 = 3.33hrs
Description : A boat man lakes 5hrs 30 mins to row a boat 30km downstream of a river and 4 hrs 15mints to cover a distance of 10km upstream. Find the speed of the river current in km/hr. A) 1.5 km/hr B) 3km/hr C) 5km/hr D) 7 km/hr
Last Answer : ANSWER: A Explanation: Rate downstream = (30 / 5 ½ ) km/hr = 30 / (11/2) km/hr = 30 * 2 / 11 km/hr = 60/11 km/hr Rate upstream = (10 / 4 ¼)km/hr = 10 / (17/4)km/hr = 10 * 4 / 17 km/hr = ... Speed of current = 1 / 2 (a - b) km/hr =1 / 2 (60 / 11 - 40 / 17) = 1.5 km/hr (approx.)
Description : A boat takes 4hours for traveling downstream from point P to point Q and coming back to point P upstream. If the velocity of the stream is 2km ph and the speed of the boat in still water is 4kmph, what is the distance between P and Q? A.9 km B.7 km C.5 km D.6km
Last Answer : Answer- D Basic Formula: Speed of stream = ½ (a-b) km/hr Speed of still water = ½ (a+b) km/hr Explanation: Time taken by boat to travel upstream and downstream = 4 hours Velocity of the stream, ½ (a-b) = 2km/hr a ... + x / 6 = 4 3x + x / 6 = 4 4x = 24 so,x = 6 distance between P and Q = 6km
Description : A man can row 9 (1/3) kmph in still water and finds that it takes him thrice as much time to row up than as to row down the same distance in the river. What is speed of the current ? A. 5km/hr B.3(1/2) km/hr C.4 (2/3) km/hr D.8 (3/2)km/hr
Last Answer : Answer- C Basic Formula: Speed of current = ½ (a-b) km/hr Explanation: Let man's rate upstream be x km/hr. Then his rate downstream is 3 x km/hr Given: Speed in still water = 9 (1/3) = 28/3 km/hr i.e, ½ (a+b) = ... the current = ½ (a-b) = ½ (14 - 14/3) = ½ (42-14/3) = 28/6 = 4 (2/3) km/hr
Description : A boat takes 38 hrs for travelling downstream from point p to point q and coming back to a point r midway between p and q. If the velocity of the stream is 8 km/hr and the speed of the boat in still water is 28 km/hr. What is the distance between p and q? A) 720 B) 640 C) 510 D) 450
Last Answer : ANSWER: A Explanation: Speed downstream = (28 + 8)km/hr = 36 km/hr Speed upstream = (28 – 8)km/hr = 20 km/hr Let the distance between p and q be ‘x’km Then, x/36 + (x/2)/20 = 38 x/36 +x/40 = 38 19x = 13680 X = 720 km Therefore the distance between p and q is 720km
Description : A train travels between two stations 15 km apart in 18 minutes. If the train accelerates for a part of journey uniformly followed by uniform retardation, the maximum speed attained by the train during the journey will by a.125 km/hr b.107 dynes c.80 km/hr d.100 km/hr e.60 km/hr
Last Answer : d. 100 km/hr
Description : A train travels between two stations 15 km, apart in 18 minutes. If the train accelerates for a part of journey uniformly followed by uniform relardation, the maximum speed attained by the train, during, the journey, will be a.60 km/hr b.80 km/hr c.125 km/hr d.100 km/hr e.107 dynes
Description : Anand leaves his house at 8.30 A.M for his school. The school is 2 km away and classes start at 9.00 A.M. If he walks at a speed of 3 km/h for the first kilometre, at what speed should he walk the second kilometre to reach just in time? -Science
Last Answer : speed=distancetimespeed=distancetime or time=distancespeedtime=distancespeed For travelling 1 km with 3 km/hr, Time taken = 1/3 hr = 20 min Now he has to reach school in 30 min,So he has cover another 1 km in = 30 -20 =10 min= 1/6 hr So speed should = distance /time= 1/(1/6) = 6 km/hr