Question

How long will a train 100m long travelling at 72kmph take to overtake another train 200m long travelling at 54kmph ? Select one: a. 70sec b. 1 min 15 sec c. 55 sec d. 1min

Answer 1

Answer:

b or d = 1 min

Explanation:

hope it helps.

Answer 2

Answer:

Required time is 1 min.

Option (b) is the correct answer.

Explanation:

Given,

Length of the first train is 100 m and second train is 200 m.

Speed of first train is 72 km/h=

$72 \times \frac{5}{18}$

=20 m/s

Speed of second train is 54 kmph=

$54 \times \frac{5}{18}$

=15 mps.

The train has to travel

$(200+100)m=300m$

to overtake the other one.

Resultant velocity=

$(20-15)m/s = 5 \: m/s$

We know, First train take time to overtake the second train

$= \frac{distance}{resistance \: velocity} = \frac{300}{5} = 60 \: s \: = 1 \: min$