AMCAT Quantitative Ability Previous Papers-5

A man in a train notices that he can count 41 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed is the train travelling?
60 km/hr
100 km/hr
110 km/hr
120 km/hr
Answer And Explanation
Answer: Option D

 

Explanation:

 

Number of gaps between 41 poles = 40
So total distance between 41 poles = 40*50
= 2000 meter = 2 km
In 1 minute train is moving 2 km/minute.
Speed in hour = 2*60 = 120 km/hour

 

A person travels equal distances with speed of 3 km/hr, 4 km/hr and 5 km/hr and takes a total of 47 minutes. Find the total distane
3 km
4 km
6 km
9 km
Answer And Explanation
Answer: Option A

 

Explanation:

 

Let the distance be 3x km,
then,
x/3+x/4+x/5=47/60
47x/60=47/60
x=1

 

So total distance = 3*1 = 3 Km

 

Ques. A walks around a circular field at the rate of one round per hour while B runs around it at the rate of six rounds per hour. They start at same point at 7:30 am. They shall first cross each other at ?
7:15 am
7:30 am
7: 42 am
7:50 am
Answer And Explanation
Answer: Option C

 

Explanation:

 

Relative speed between two = 6-1 = 5 round per hour

 

They will cross when one round will complete with relative speed,
which is 1/5 hour = 12 mins.

 

So 7:30 + 12 mins = 7:42

 

The ratio between the speeds of two trains is 7: 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is ?
83.5 km/hr
84.5 km/hr
86.5 km/hr
87.5 km/hr
Answer And Explanation
Answer: Option D

 

Explanation:

 

Let the speeds of two trains be 7X and 8X km/hr.

 

8X=400/4
=>X=12.5Km/hr

 

So speed of first train is 12.5*7 = 87.5 km/hr
Ques. A man can row upstream 10 kmph and downstream 20 kmph. Find the man rate in still water and rate of the stream.
0,5
5,5
15,5
10,5
Answer And Explanation
Answer: Option C

 

Explanation:

 

Please remember,
If a is rate downstream and b is rate upstream
Rate in still water = 1/2(a+b)
Rate of current = 1/2(a-b)

 

=> Rate in still water = 1/2(20+10) = 15 kmph
=> Rate of current = 1/2(20-10) = 5 kmph