Two trains are moving in opposite directions at speeds of 80 km/h and 70 km/h. The length of one train is 180 m. The time taken by them to cross each other is 19 seconds. The length (in m) of the other train, correct to 2 decimal places, is:

Correct option is B

Given:

Speed of Train A = 80 km/h

Speed of Train B = 70 km/h

Length of Train A = 180 m

Time to cross each other = 19 seconds

Concept Used:

Distance = Relative Speed × Time

Change to km/h to m/s = $$\frac{5}{18}$$​

Solution:

Relative speed = (80+70)× $$\frac{5}{18} = 150 \times \frac{5}{18} = \frac{375}{9}$$​

Total distance = Relative speed × Time = $$\frac{375}{9} \times 19$$  $$=\frac{7125}9$$​​

Length of second train = $$\frac{7125}9 – 180$$​

= $$\frac{7125- 1620}3$$​​

= 611.66 m