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 : 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 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 : 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 : A woman rows to a place 24km distant and come back in 7 hrs. She finds that she can row 2km with the stream in the same time as 1.5km against the stream. The rate of the stream is, A) 2 B) 4 C) 1 D) 3
Last Answer : ANSWER: C Explanation: Suppose she move 2km downstream in x hrs Then, speed of downstream = (2/x) km/hr Speed of upstream = (1.5/x) km/hr Therefore 24/(2/x) + 24/(1.5/x) = 7 12x + 16x = 7 ... of downstream = 8km/hr and upstream = 6km/hr Rate of the stream = ½ (8 - 6 )km/hr = 1 km/hr
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 : 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 : At the same speed a boat travelling 50km upstream and 78km downstream in 16hrs. Also it can travel 70km upstream and 104km downstream, in 22hrs at the same speed of the stream is. A) 5km/hr B) 3km/hr C) 4km/hr D) 2km/hr
Last Answer : ANSWER : C
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 : 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 : 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 boy rows 1500m in 1350 seconds against the stream and returns in 15 minutes. His rowing speed in still water is. A) 5km/hr B) 4km/hr C) 7km/hr D) 9km/hr
Last Answer : ANSWER : A Explanation: Rate upstream = (1500 / 1350) m/s = (150/135) m/s = 10/9 m/s Rate downstream = (1500 / 900)m/s = (15/9)m/s = 5/3 m/s Rate in still water = ½ [ a+ b] = ½[10 / 9 + 5 /3 ... +15 / 9] = ½[25/9] = 25/18 m/s = (25/18) * (18/5)km/hr speed in still water = 5km/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 : 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 : 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 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 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 : 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 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 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 : 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 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 : If the speed of boat is 5 km/hr and speed of stream is 2 km/hr. What is the speed of the boat in Upstream? a) 5km/hr b) 2km/hr c) 7km/hr d) 3km/hr
Last Answer : d) 3km/hr
Description : If the speed of the boat is 5 km/hr and the speed of stream is 2 km/hr, what is the speed of the boat Downstream? a) 5km/hr b) 2km/hr c) 7km/hr d) 3km/hr
Last Answer : c) 7km/hr
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 : 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 : 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 : 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 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 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 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 man can row 4 km against the stream in 40mins and return in 36mins. Find the rate of current. A) 1/2 km/hr B) 1/3 km/hr C) 2/3 km/hr D) 1/4 km/hr
Last Answer : ANSWER: B Explanation: Speed of the man (upstream) = (4 / 40 * 60) km/hr = 6 km/hr Speed of the man (downstream) = ( 4 / 36 * 60) km/hr = (60 / 9)km/hr = 20/3 km/h Rate of the current = ½[downstream ... 6] km/hr = ½ [ 20 - 18/3] km/hr = ½ [2/3]km/hr Rate of the current = 1/3 km/hr
Description : A boatman can take the same time to row6.5km downstream and 3.5km upstream. His speed in still water 2.5 km/hr. The speed of the stream is. A) 0.75 km/hr B) 2.5 km/hr C) 1.5km/hr D) 7.5km/hr
Last Answer : ANSWER: A Explanation: Given that the speed in still water = 2.5 km/hr Let the speed of the stream be x; km/hr speed in upstream = (2.5 - x)km/hr Then time taken to cover 6.5 km downstream = 6.5 / (2.5+x) ... 5x = 8.75 + 3.5x 10 x = 7.5 x = 0.75 km/hr The speed of the stream is 0.75 km/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 : A train 330 m long passes a man, running at 18 km/hr in the direction opposite to that of the train in 18 seconds. The speed of the train is. A) 38 km/hr B) 29km/hr C) 48km/hr D) 44km/hr
Last Answer : ANSWER: C Explanation: Length of the train = 330 m Speed = distance / time. Speed of the train relative to man = 330 / 18 m/s = 110 / 6 m/s Convert m/s into km/hr Therefore 110 / 6 m/s = (110 / ... (x +18) = 66 km/hr X + 18 = 66 X = 48 Therefore the speed of the train is 48 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 : 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 : A boat takes 27 hrs to travel a distance upstream and takes 9hrs to travel the same distance downstream. If the speed of the boat in still water is 12km/hr, then what is the velocity of the stream? A) 8km/hr B) 6km/hr C) 4km/hr D) None of these
Last Answer : ANSWER : B Explanation: Let the velocity of the stream be ‘ y’ km/hr Then the speed of the downstream = (12 + y)km/hr The speed of the upstream = (12 – y)km/hr 9 (12 + y) = 27 (12 – y) 108 + 9y = 324 – 27y 27y + 9y = 324 - 108 36y = 216 y = 6 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 : Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train? A.27 7/9 m B.28 m C.29 m D.30 2/7 m E.None of these
Last Answer : Answer – A (27 7/9 m) Explanation – When SAME direction- MINUS Relative speed = (40-20) km/hr = [20 x 5/18] m/sec = [50/9] m/sec. Length of faster train = sxt=[50/9 x 5] m = 250/9 m = 27 7/9 m.
Description : A train 560 m long crosses the platform of length 340 m in 45seconds. Find the speed of the train in km/hr A) 72km/hr B) 36km/hr C) 48km/hr D) 15km/hr
Last Answer : ANSWER:A Explanation: Length of the train = 560 m Length of the platform = 340 m Therefore, length of the train + length of the platform = 560 m + 340 m = 900 m Time taken by the train to cross the ... to km/hr, multiply by 18/5 Therefore, speed of the train = 20 18/5 km/hr = 72 km/hr
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 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 : Sakthi rows a boat at 4 km upstream in 1hour and 1 km downstream in 20 minutes. How long will he take to reach 3.5km in still water? A) 1 B) 2 C) 3 D) 4
Last Answer : ANSWER:A Explanation: Upstream Speed = 4/1 = 4km/hr Downstream Speed = 1/20 = 0.05 km/min = 0.05*60 = 3 km/hr Hence, speed of boat = 1/2( Upstream Speed + Downstream Speed) = 1/2 (4+3 ... , the time required to reach the distance of 3.5 km=DistanceCovered/Speed of boat = 3.5/3.5km/hr =1 km/hr
Description : X, Y , Z are three towns on a lake which flows uniformly. Y is equidistant from X and Z. A man rows from X to Y and returns in 20hrs. He can row from X to Z in 8 hr. The ratio of speed of the man in still water to the speed of the current is. A) 3:5 B) 5:3 C) 2:3 D) None of these
Last Answer : ANSWER: A Explanation: Let the speed of man in still water = x km/hr Speed of the current = y km/hr Speed of downstream = (x+ y) km/hr Speed of upstream = ( x - y) km/hr Let the lake be flowing from X to Z and xy = yz a ... y = 1 / 4 4x - 4y = x + y 3x = 5y x / y = 3 / 5 x : y = 3 : 5
Description : A girl can row 15 kmph in still water and he finds that it takes him thrice as long to row up as to row down the river. Find the rate of stream. A) 2.5 B) 5.5 C) 7.5 D) 12.5
Last Answer : Answer: C Explanation: Given that, time taken to travel upstream = 3 time taken to travel downstream When distance is constant, speed is inversely proportional to the time Hence, 3 speed upstream = speed downstream ... ., speed upstream =7. 5 km/hr Rate of stream =1/2(3x−x)= x = 7.5km/hr
Description : A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is: a) 35.55 km/hr b) 36 km/hr c) 71.11 km/hr d) 71 km/hr e) 69.69km/hr
Last Answer : Total time taken = (160/64) + (160/80) = 9/2 hrs. Avg Speed – 320 × (2/9) km/hr = 71.11km/hr Answer: c)
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