Mathematics Mcqs

A man travels a distance of 2 km by walking at a speed of 6 km/hr. He returns back at a speed of 4 km/hr. What is his average speed?

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A man travels a distance of 2 km by walking at a speed of 6 km/hr. He returns back at a speed of 4 km/hr. What is his average speed?

A. 4.5 kmph
B. 4.8 kmph
C. 5 kmph
D. 5.1 kmph
Time taken for the forward journey
= 2/6 = (1/3) hrs Time taken for the return journey
= 2/4 = (1/2) hrs Total time = 5/6 hrs Average speed = 4/(5/6) = 24/5 = 4.8kmph

A man rows at a speed of 6 km/hr in still water. If the time taken to row a certain distance upstream is 4 times the time taken to row the same distance downstream, what is the speed of the river?

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A man rows at a speed of 6 km/hr in still water. If the time taken to row a certain distance upstream is 4 times the time taken to row the same distance downstream, what is the speed of the river?

A. 1.8 km/hr
B. 3 km/hr
C. 3.6 km/hr
D. 4 km/hr
Let x be the speed of the river.
Ds = (6 + x) km/hr; Us = (6 – x) km/hr
If t hours is the time to row downstream then 4t hours is the time to row upstream.
(6 + x)*t = (6 – x)*4t
6 + x = 24 – 4x
x = 3.6 km/hr

Two trains 140 metres and 120 metres are running in the same direction with speeds 40 kmph and 60 kmph respectively. In what time will the faster train pass the slower one?

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Two trains 140 metres and 120 metres are running in the same direction with speeds 40 kmph and 60 kmph respectively. In what time will the faster train pass the slower one?

A. 0.60 minutes
B. 0.36 minutes
C. 0.78 minutes
D. 0.42 minutes
Total distance = addition of length of the two trains = 140 + 120 = 260 metres
As the two trains are travelling in the same direction, their relative speed is:
v = | v1 – v2 | = | 40 – 60 | = 20 km/hr = 20*1000/60 = 1000/3 metres/min
t = 260/ 1000*3
t = 0.78 minutes

If the ratio of the speeds of A and B to cover a distance of 200 m is 3:4, then the ratio of the time taken to cover the same distance is________?

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If the ratio of the speeds of A and B to cover a distance of 200 m is 3:4, then the ratio of the time taken to cover the same distance is________?

A. 6:8
B. 3:7
C. 5:4
D. 4:3
If the ratio of the speeds of two objects is a:b, then the time taken by them to cover the same distance is
b:a Hence, the answer is 4:3

A boats man can row in still water at speed of 7 km/hr. It takes 6 hours more to travel the same distance in upstream than in downstream if the speed of the river is 3 km/hr. what is the distance between the two destinations?

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A boats man can row in still water at speed of 7 km/hr. It takes 6 hours more to travel the same distance in upstream than in downstream if the speed of the river is 3 km/hr. what is the distance between the two destinations?

A. 20 km
B. 40 km
C. 30 km
D. 10 km
x = 7 km/hr ; y = 3 km/hr
Ds = 10 km/hr ; Us = 4 km/hr
Distance (d) is same. Therefore, if time taken for downstream is t hours, the time for upstream is (t + 6) hours.
10*t = 4*(t + 6)
6t = 24 ; t = 4 hours
d = 10*4 = 40 km

If Afnan drives at 4/5th of his usual speed to his office, he is 6 minutes late. What is his usual time to reach his office?

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If Afnan drives at 4/5th of his usual speed to his office, he is 6 minutes late. What is his usual time to reach his office?

A. 36
B. 24
C. 30
D. 18
Let t be his usual time to reach his office and v be his usual speed.
v = d/t ……….(d is the distance Afnan travels while going to his office)
vt = d
At v1 = 4v/5 ; t1 = t + 6
4v/5 = d/(t + 6)
4v/5* (t + 6) = d
4v/5* (t + 6) = vt
On solving we get,
t = 24 minutes

Two boys starts from the same place walking at the rate of 5 kmph and 5.5 kmph respectively in the same direction. What time will they take to be 8.5 km apart?

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Two boys starts from the same place walking at the rate of 5 kmph and 5.5 kmph respectively in the same direction. What time will they take to be 8.5 km apart?

A. 17 hr
B. 14 hr
C. 12 hr
D. 19 hr
Relative speed = 5.5 – 5 = .5 kmph (because they walk in the same direction)
distance = 8.5 km
time = distance/speed=8.5/.5=17 hr

A cyclist covers a certain distance in 50 minutes at a speed of 24 kmph. To cover the same distance in 40 minutes, he should travel at a speed of__________?

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A cyclist covers a certain distance in 50 minutes at a speed of 24 kmph. To cover the same distance in 40 minutes, he should travel at a speed of__________?

A. 30 kmph
B. 27 kmph
C. 25 kmph
D. 20 kmph
Distance = 24*50/60 = 20 km New Speed = 20/(40/60)) = 30 kmph