Description : A man rows to a place 48km distant and back in 14 hours. He finds that he can row 4km with the stream in the same time as 3km against the stream. Find the rate of the stream. A.2 km/hr B.1 km/hr C.3 km/hr D.3.5km/hr
Last Answer : Answer- B Basic Formula: Speed of the stream = ½ (a-b) km / hr Speed = distance traveled / time taken Explanation: Suppose he moves 4km downstream in x hours Then, downstream a= 4 / x km/hr Speed upstream b = 3/ x km/hr ... = 1/2 a=8 km/hr ,b = 6 km/hr rate of stream = ½ (8 - 6 ) = 1 km/hr
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 : Sham can row a boat at 10kmph in still water. IF the speed of the stream is 6kmph, the time taken to row a distance of 80km down the stream is A.4 hours B.5hours C.3 hours D.2 hours
Last Answer : Answer- B Basic Formula: Speed of stream = ½ (a-b) km/hr Speed in still water = ½ (a+b) km/hr Explanation: Given: Speed in still water, ½ (a+b) = 10 km/hr a+b = 20 km/hr .(1) ... ) we get 2a = 32 a = 16 km/hr speed downstream =distance traveled / time taken time taken = 80/16 = 5 hours
Description : A boys rows to a certain place and comes back, but by mistake he covers 2/3rd more distance while coming back. The total time for this journey is 20 hours. The ratio of speed of boat to that of ... starting point from his present position? A) 2hr 13mints B)1hr 30 mins C) 2hr 30mins D)1hr 40 mins
Last Answer : ANSWER : A Explanation: let speed of boat and stream be 2x and x respectively So downstream speed = 2x+x = 3x, and upstream speed = 2x-x = x Let total distance between points is d km So he covered d ... with speed 3x = 48 km/hr(downstream) So time is 80/36 * 60 = 133.33 minutes = 2hr 13mins
Description : A man rows 750m in 775 seconds against the stream and returns in 7 1/2 minutes. What is rowing speed in still water ? A.4.7km/hr B. 4km/hr C.3.5km/hr D.6km/hr
Last Answer : Answer-A Basic Formula: i) Speed in still water = ½ (a+b) kmph where a' is speed downstream and b' is speed upstream ii) a km / hr = a x 5/18 m /s iii) a m/sec = a x 18/5 km/hr Explanation: Speed upstream b' ... (750/450 + 750/675 ) x 18/5 km/hr = ½ (5/3 + 30/31) x 18/5 km/hr = 4.7 km/hr
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 this usual rowing rate, Mohit can travel 12 miles downstream in a certain river in 6 hours less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his 24 miles round trip, ... current in miles per hour? A.2.5m/hr B.4 m/hr C.8/3 m/hr D. 5/3m/hr
Last Answer : Answer-C Basic Formula: Speed of the stream = ½ (a-b) km/hr Explanation: Let the speed in still water be x m/hr Speed of stream be y m/hr Then, speed upstream = x-y m/hr and Speed downstream = x+y m/hr 12/x-y - ... 1] 3y^2 = 8 y so, y = 8/3 speed of the current = 8/3 m/hr = 2 (2/3) m/hr
Description : There is road besides a river. Two friends started from a place P, moved to a shopping mall situated at another place Q and then returned to P again. One of them moves on a cycle at a speed of 12 km/ ... which of the two friends will return to place P? A. Both B. Boater C. Cyclist D. None of these
Last Answer : Answer-C Explanation: The cyclist moves both ways at a speed of 12khr so average speed fo the cyclist - 12 km/hr boat sailor moves downstream at 10+4 = 14km/hr and upstream 10- 4 = 6km/hr ... 8.4km/hr The average speed of cyclist is greater .so,cyclist comes first and return to place P.
Description : Ashok can row upstream at 8kmph and downstream at 12kmph.What is the speed of the stream ? A.6km/hr B.3km/h C.2 km/hr D.4km/hr
Last Answer : Answer -C Basic Formula: If the speed downstream is a kmph and the speed upstream is b kmph then Speed of the stream = ½ (a-b) kmph Explanation: Speed downstream a = 12kmph Speed upstream b = 8 kmph Speed of the stream = ½ (a-b) = ½ (12-8) = 4/2 = 2 kmph speed of the stream = 2kmph
Description : A train 125 m long passes a man, running at 5 kmph in the same direction in which the train is going, in 10 seconds. The speed of the train is: A.35 km/hr B.50 km/hr C.48 km/hr D.55 km/hr E.None of these
Last Answer : Answer – B (50 km/hr) Explanation – Let speed be S Relative speed = total lengths/time [ in this case man length is neglible compare to train so neglected] (S – 5) x 5/18 = 125 /10 S- 5 = (125/10)x(18/5) S-5 = 45 S=50 km/hr
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 : The distance between two cities A and B is 330 km. A train starts from A at 8 a.m. and travels towards B at 60 km/hr. Another train starts from B at 9 a.m. and travels towards A at 75 km/hr. At what time do they meet? A.10:30 am B.10:45 am C.11 am D.11:25 am E.None of these
Last Answer : Answer – C (11 am) Explanation – Suppose they meet x hrs after 8 a.m. Then, (Distance moved by first in x hrs) + [Distance moved by second in (x-1) hrs] = 330 60x + 75(x – 1) = 330 x = 3 So, they meet at (8 + 3), i.e. 11 a.m
Description : Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is: A.1 : 3 B.3 : 4 C.3 : 2 D.Data inadequate E.None of these
Last Answer : Answer - C (3 : 2) Explanation - Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train = 27x metres, and length of the second train = 17y metres. relative speed = total ... 23x + 23y = 27x + 17 y 27x-23x= 23 y-17y 4x=6y x/y=6/4=3/2= 3:2
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 : If Nishu can swim downstream at 6kmph and upstream at 2kmph.What is his speed in still water ? A.5 km/hr B.4 km/hr C.8km/hr D.7km/hr
Last Answer : Answer- B Basic Formula: If the speed downloadstream is a km/ hr and the speed upstream is b km/ hr then Speed in still water is = ½ (a+b) km / hr [memory tool last 2 L cross and make +] Explanation: Given ... still water = ½ (a+b) kmph = ½ (6+2) = 8/2 = 4kmph speed in still water = 4kmph
Description : A train overtakes two persons walking along a railway track. The first one walks at 4.5 km/hr. The other one walks at 5.4 km/hr. The train needs 8.4 and 8.5 seconds respectively to overtake them. What is the speed ... as the train? A.59 km/hr B.65 km/hr C.70 km/hr D.81 km/hr E. None of these
Last Answer : Answer-D (81 km/hr) Explanation4.5 km/hr =(4.5 x 5/18)m/sec =5m/4sec = 1.25 m/sec, and 5.4 km/hr =(5.4 x 5/18)m/sec =3m/2sec = 1.5 m/sec. Let the speed of the train be x m/sec. Then, (x - 1.25) ... - 12.75 => 0.1x = 2.25 => x = 22.5 Therefore Speed of the train =(22.5 x18 /5)km/hr = 81 km/hr.
Description : Two, trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is: A. 1: 2 B. 4 : 3 C. 7 : 8 D. 3 : 4 E. none of these
Last Answer : Answer- B (4:3) Explanation: Let us name the trains as A and B. Then, trick formula (A’s speed) : (B’s speed) = square root of b : square-root of a =square-root of 16 : square-root of 9 = 4 : 3.
Description : Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is: A.40 m B.55 m C.65 m D.50 m E.None of these
Last Answer : Answer- D (50) Explanation – Relative speed= total lengths/time (46-36) x 5/18 = [L + L ] / 36 10 x (5/18) x36 x (1/2)= L L=50 m
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 train travelling at a speed of 75 mph enters a tunnel 7/2 miles long. The train is 1/4 mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges? A.1 min B.3 min C.5 min D.6 min E.None of these
Last Answer : Answer – B (3 min) Explanation – Actually train is covering length of tunnel + its own length here so total distance = 7/2 + 1/4= 15/4 miles time= distance /speed time= (15/4) / 75 = 1/20 hour (1/20)x60 = 3 min
Description : A 270 m long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train? A.180 B.230 C.245 D.235 E.None of these
Last Answer : Answer – B (230) Explanation – Relative speed = total lenghths /time [120 +80] x5/18 ={ 270 + other train length (say L) } / 9 sec (x5/18 to convert km/hr to m/sec ) 200 x (5/18) x9 = 270 + L 500 = 270 +L L=230 m Note: always do cutting ,avoid solving exact
Description : A mototboat can row to a place 112 km away and come back in 44 hours. The time to row 42 km with the stream is same as the time to row 24 km against the stream. Find the speed of boat in still water. A) 5.5 km/hr B) 7.5km/hr C) 10.5 km/hr D) 3.5 km/hr
Last Answer : ANSWER: A Explanation: Downstream speed = 42/x km/hr Upstream speed = 24/x km/hr 112 / (42 / x) + 112 / (24 / x) = 44 112[x /42 + x / 24] = 44 112 / 3 [x / 14 + x / 8] = 44 11x / 56 = 44 * ... = 4 km/hr Speed of boat = 1/2 * (7 + 4) km/hr = 11 /2 speed of boat in still water = 5.5 km/hr
Description : A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform? A.310 m B.350 m C.600 m D.490 m E.None of these
Last Answer : Answer - B (350 m) Explanation - when it cross a pole actually it is crossing itself so, S = 300/18 let length of platform be p relative speed = total lengths/time speed of ... pole,man and other is of considerable length like platform ,bridge. when train crosses pole,man it crosses itself
Description : A man can row 15 km/hr in still water. It takes him twice as long to row upstream as to row downstream. Find the rate of stream? a) 5 km/hr b) 10 km/hr c) 7.5 km/hr d) 6 km/hr e) 8 km/hr
Last Answer : Let the man’s upstream speed be x km/hour and downstream speed will be 2x km/hour Speed in still water = 1/2 (2x + x) = 3x/2 km/hour 3x/2 = 15 X = 10 Hence, his downstream speed = 20km/hour Rate of stream = 1/2 (20-10) = 5km/hour Answer: a)
Description : A fisherman rows to a place 24km distance and back in 7 hours. He finds that he can row 2km with the stream in the same time 1.5 km against the stream.The rate of the stream is? A) 7 B) 5 C) 3 D) 1
Last Answer : Answer: D Explanation: Let be moves 2 km downstream in x Hours Then in speed downstream = 2/x kmph Speed in upstream = 1.5/x kmph ==> 24/2/X + 24/1.5/X = 7 12x+16x=7 Therefore x=1/4 Speed in downstream = 8 Kmph Speed in upstream = 6 Kmph Then the Rate of stream = 1/2 (8 - 6) = 1 Kmph
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 : A boat cover a certain distance downstream in 2hr while it comeback 3/2hrs.If the speed of the stream be 4kmph.what is the speed of the boat in still water? 1)21kmph 2)18kmph 3)22kmph 4)12kmph
Last Answer : 1)21kmph Exp:(x+3) ×2=(x-3)(3/2)=>21.
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 person covered a certain distance by bus at the rate of 40 kmph and walked back to the initial point at the rate of 6 kmph. The whole journey took 13 hours and 48 minutes. What distance did he walk? a) 60km b) 64 km c) 70km d) 72km e) 80 km
Last Answer : Let the distance be x km. then (x/40) + (x/6) = 13 + (48/60) = 69/5 Answer is: d)
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 goes 3.5km upstream in 24 mins and the speed of the stream is 1.5km per hour, then the speed of the boat in still water is. A) 4.3 km/hr B) 7.4 km/hr C) 5.2km/hr D) 10.25km/hr
Last Answer : ANSWER: D Explanation: Speed of upstream = 3.5 / 24 km/min = 3.5 / 24 * 60 km/hr = 8.75 km/hr Speed of the stream = ½ (a - b)km/hr = 1.5 km/hr 1.5 = ½ ( a- 8.75)km/hr a = 11.75 km/hr ... (a + b) km/hr = ½ (11.75 + 8.75) = ½(20.5) The speed of the boat in still water = 10.25 km/hr
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 : A boat goes 30 km upstream and 44 km downstream in 10 hours. In 13 hours it can go 40 km upstream and 55 km downstream. Then what is the speed of the stream? (a) 3km/hr (b) 5km/hr (c) 6km/hr (d) 7km/hr
Last Answer : (a) 3km/hr
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 : Excluding the stoppages, the speed of a bus is 64 km/hr and including the stoppages the speed of the bus is 48km/hr. For how many minutes does the bus stop per hour? 1) 15 min 2) 10 min 3) 12 min 4) 20 min 5) 18 min
Last Answer : 1) 15 min
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 : Busses start from a bus terminal with a speed of 20 km/hr at intervals of 10 minutes. What is the speed of a man coming from the opposite direction towards the bus terminal if he meets the buses at intervals of 8 minutes? a) 3 km/hr b) 4 km/hr c) 5 km/hr d) 7 km/hr e) None of these
Last Answer : Distance covered in 10 minutes at 20 kmph = distance covered in 8 minutes at (20+x) kmph 20× 10/60=8/60(20+x) 200 = 160 + 8x 8x = 40 x=40/8=5 kmph Answer: c)
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 thief is noticed by a policeman from a distance of 200 m. The thief starts running and the policeman chases him. The thief and the policeman run at the rate of 10 km and 11 km per hour respectively. What is the distance between them after 6 minutes? A.100 m B.150 m C.190 m D.200 m E.None of these
Last Answer : Answer- A(100m) Explanation: Relative speed of the thief and policeman = (11 – 10) km/hr = 1 km/hr Distance covered in 6 minutes =[(1/60)*6] km = (1/10)km = 100 m. Distance between the thief and policeman = (200 – 100) m = 100 m.
Description : Two trains starting at the same time from two stations 200 km apart and going in opposite directions cross each other at a distance of 110 km from one of the stations. What is the ratio of their speeds? A.9 : 28 B.11 : 9 C.11 : 8 D.9 : 22 E.None of these
Last Answer : Answer – B (11 : 9) Explanation – In the same time, they cover 110 km and 90 km respectively.Ratio of their speeds = 110 : 90 = 11 : 9
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 boat is rowed downstream at 15.5 km/h and upstream at 8.5 km/h. The speed of the stream is: (a) 3.5 km/h (b) 5.75 km/h (c) 6.5 km/h (d) 7 km/h
Last Answer : (a) 3.5 km/h
Description : A boat covers 14 kms in upstream and 20 kms downstream in 7 hours. Also it covers 22 kms upstream and 34 kms downstream in 10 hours. Find the speed of the boat in still water and of that the stream. -Maths 9th
Last Answer : Given, The boat covers 14 km upstream and 20km downstream . at time 7 hours also cover 22km ups. and 34km dwn in10 hours total speed = total distance/total time :.total distance = 14+20+22+34=90km and total time=7+10= ... =90/17 => 5.294km/h => 5.294km/h the speed of boat in still water is 5.29 km/h
Description : 24 14 26 ? 28 16 30 a) 13 b) 17 c) 15 d) 11 e) 20
Last Answer : The series consists of two series 1 and 2: Series 1 : 24 26 28 30 +2 +2 +2 Series 2 : 14 15 16 +1 +1 Answer: c)
Description : A and B started a business jointly. A’s investment was thrice the investment of B and the period of his investment was two times the period of investment of B. If B received Rs.4000 as profit, then their total profit is : a) Rs.16,000 b) Rs.20,000 c) Rs.24,000 d) Rs.28,000 e) None of these
Last Answer : Suppose B invested Rs. x for y months. Then, A invested Rs.3x for 2y months. So, A : B = (3x × 2y) : (x × y) = 6xy : xy = 6 : 1 So, B’s profit : total profit = 1 : 7 Let the total profit be Rs. x. Then, 1 / 7 = 40000 / x Or x = 28000. Answer: d)
Description : The speed of a car increases by 2 kms after every one hour. If the distance travelled in the first one hour was 35 kms, what was the total distance traveled in 12 hours? A.456 kms B.482 kms C.552 kms D.556 kms E.None of these
Last Answer : Answer – C (552 kms) Explanation – Total distance travelled in 12 hours = (35 + 37 + 39 + …… upto 12 terms) This is an A.P. with first term, a = 35, number of terms, n = 12, common difference, d =2. Required distance =12/2 (2 x 35 + (12 – 1) x 2) = 6(70 + 22) = 552 kms
Description : The average age of two persons is 46 years. 16 years back the ratio between their ages were 1 : 2, then what is the difference between present ages of these two persons? 1) 16 years 2) 20 years 3) 24 years 4) 12 years 5) 8 years
Last Answer : 2) 20 years
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 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.