Question

How much time does a train $50$ m long moving at $68$ km/hr take to pass another train $75$ m long moving at $50$ km/hr in the same direction?

• A. $5$ seconds
• B. $10$ seconds
• C. $20$ seconds
• D. $25$ seconds

Answer 1

The correct option is D $25$ seconds

Since the trains are moving in the same direction the relative speed of the faster train w.r.t. the slower train $=$ Difference of their speeds
$=(68-50)$ km/hr $=18$ km/hr $=$ $(18\times \frac{5}{18})$ m/sec $=5$ m/sec
Distance travelled $=$ Sum of the lengths of the two trains $=(50+75)$ m $=125$ m
$\therefore$ Required time $=$ $\frac{125}{5}$ second $=25$ seconds