Question

Word count: 1
Two trains 120 m and 80 m in length are running in opposite direction with velocities 42 km/h
and 30 km/hr . In what time they will completely cross each other?
Answer:
LX 날
I​

Answer 1

Answer:

60 secs

Explanation:

time to cross completely is given by

(sum of distances) /relative velocity

Relative velocity is 12Km/hr or 3.33m/sec

time hence is

$\frac{120 + 80}{ \frac{10}{3} } = 60$

Answer 2

Answer:

Time taken to cross each other completely 10 seconds

Explanation:

As they are moving in opposite directions relative velocity will be the sum of given two velocities which is 72 km/h or, 20 m/s

then,

time taken to cross each other = (sum of lengths or distances)/(relative velocity)

which is,

200/20

time taken = 10 seconds