Practice question on time ,speed and distance

time ,speed and distance

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Question no. 1

A man makes his upward journey at 16 km/h and downward journey at 28 km/h. What is his average speed ?

looks_one 32

looks_two 56

looks_3 20.36

looks_4 22

Option looks_3 20.36

Solution :
let the distance travel is x

Question no. 2

During a journey of 80 km a train covers first 60km with a speed of 40 km/h and completes the remaining distance with a speed of 20 km/h. What is the average speed of the train during the whole journey?

looks_one 30

looks_two 32

looks_3 36

looks_4 None of these

Option looks_two 32

Solution :
total distance = 80 km
time taken to cover first 60 km = 60/40 = 1.5 hr
time taken to cover remaining 20 km = 20/20 = 1 hr
total time = 1.5 + 1 = 2.5 hr

Question no. 3

A train running between two stations A and B arrives at its destination 10 minutes late when its speed is 50 km/h and 50 minutes late when its speed is 30km/h. What is the distance between the stations A and B ?

looks_one 40 km

looks_two 50 km

looks_360 km

looks_4 70 km

option looks_two 50 km

Solution :
x = distance between A and B
t = time taken by train to cover the distance at time
according to question
Case 1 : late by 10 minute with speed 50km/hr

Case 2 : late by 50 minute with speed 30km/hr

solve both the equation to get the value of x
150t + 25 = 3x
150t + 125 = 5x
2x = 100
x = 50 km

Question no. 4

A motor boat whose speed is 15 km/h in still water goes 30 km downstream and comes back in four and a half hours. The speed of the stream is :

looks_one 4

looks_two 6

looks_3 7

looks_4 5

Option looks_4 5

Solution :
Speed of boat = 15km/hr
distance covered downstream or upstream = 30 km
speed of stream = x km/hr
time taken = 4.5 hr

Question no. 5

A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from the opposite direction in 6 seconds. The speed of the second train is(km/hr)

looks_one 48

looks_two 54

looks_3 66

looks_4 82

Option looks_4 82

Solution :
let the speed of second train = x km/hr
trains are crossing each other , therefore distance = length of both the train = 108 + 112 = 220 m
speed (add because of opposite direction ) = 50 + x

Question no. 6

A car travels first half distance between two places with a speed of 40 km/h and the rest of the half distance with a speed of 60 km/h. The average speed of the car is

looks_one 48

looks_two 37

looks_3 44

looks_4 None of these

Option looks_one 48

Solution :
let the distance is x

Question no. 7

A train 100 metres long passes a bridge at the rate of 72 km/hr in 25 seconds. What is the length of the bridge?

looks_one 170 m

looks_two 400 m

looks_3 600 m

looks_4 None of these

Option looks_two 400 m

Solution :
Length of bridge = x
According to question
Train passes x meter bridge in 25 second
Train cover the distance in 25 second = x + 100
Speed of train = 72 km/hr = 72 * 5/18 = 20 m/s
distance = speed * time
x + 100 = 20 * 25 = 500
x + 100 = 500
x = 400 m

Question no. 8

A train covers 180 km distance in 4 hours. Another train covers the same distance in 1 hour less. What is the difference in the distances covered by these trains in one hour ?

looks_one 45 km

looks_two 9 km

looks_3 40 km

looks_4 None of these

Option looks_4 None of these

Solution :
Train cover 180 km distance in 4 hr , speed of train = 180/4 = 45 km/hr
Another train covers 180 km distance in 3 hr , speed of second train = 180/3 = 60 km/hr
Distance cover by first train in 1 hr = 45 km
Distance cover by second train in 1 hr = 60 km
difference in distances = 60 - 45 = 15 km

Question no. 9

Starting with the initial speed of 30 km/hr, the speed is increased by 4 km/hour every two hours. How many hours will it take to cover a distance of 288 km?

looks_one 8

looks_two 4

looks_3 6

looks_4 12

Option looks_one 8

Solution :
initial speed = 30 km/hr
Speed after each two hour = 30 , 34 , 38 .....
distance cover each 2 hr = 60 , 68 , 76 ....
the distance covered is following a sequence (Arithmetic progression) , To cover the 288 km
let n is the number of 2 hr required to cover 288 km

Hour is needed = 2 * 4 = 8

Question no. 10

A train consists of 12 boggies, each boggy 15 metres long. The train crosses a telegraph post in 18 seconds. Due to some problem, two boggies were detached. The train now crosses a telegraph post in

looks_one 18 s

looks_two 12 s

looks_3 15s

looks_4None of these

Option looks_3 15s

Solution :
Total length of train (engine + boggy) = x + 12*15 = x + 180 m where x is length of engine
speed of train = (x+180)/18
Two boggies were detached , now total length of train = x + 10*15 = x + 150
let t is the time taken to cross the telegraph
t = (x+150)/ speed of train
If we ignore the length og engine
speed = 180/18 = 10 m/s
t = 150/10 = 15 s

Question no. 11

A sailor can row a boat 8 km downstream and return back to the starting point in 1 hour 40 minutes. If the speed of the stream is 2 km/h, then the speed of the boat in still water is: (Km/hr)

looks_one 5

looks_two 10

looks_3 15

looks_4 20

Option looks_two 10

Solution :
Speed of boat = x
Speed of stream = 2 km/hr
According to question

Question no. 12

A train 110 m in length travels at 60 km/h. How much time does the train take in passing a man walking at 6 km/h against the train ?

looks_one 6s

looks_two 12 s

looks_3 10 s

looks_4 18s

Option looks_one 6s

Solution :
Relative velocity = 60 + 6 = 66 km/hr = 66 * 5 /18 m/s

Question no. 13

A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30km upstream and 21 km downstream in 6 hours and 30 minutes. The speed of the stream is :

looks_one 10 km

looks_two 5 km

looks_3 4 km

looks_4 None of these

Option looks_3 4 km

Solution :
Speed of body = x
speed of stream = y
According to Question

Question no. 14

If a man travels at 30 km/h, he reaches his destination late by 10 minutes but if he travels at 42 km/h then he reaches 10 minutes earlier. The distance travelled by him is :

looks_one 30 km

looks_two 35 km

looks_3 45 km

looks_4 36 km

Option looks_two 35 km

Solution :
Destination distance = x km
t is the time to reach destination on time
Case 1 : late by 10 minutes with 30 km/hr

Case 2 : reaches 10 minutes earlier with 42 km/hr

Solve the both equation :
x = 30t + 5
x = 42t - 7
0 = -12t + 12
t = 1
x = 30 (1 + 1/6) = 35 km

Question no. 15

Two trains each of 120 m in length, run in opposite directions with a velocity of 40 m/s and 20 m/s respectively. How long will it take for the tail ends of the two trains to meet each other during the course of their journey ?

looks_one 20 s

looks_two 3 s

looks_3 4s

looks_4 5s

Option looks_3 4s

Solution :
Distance (sum of length of both the train) = 240 m
Speed (both train in opposite direction) = 40 + 20 = 60 m/s
Time = distance/speed = 240 / 60 = 4 s