Question

$150m$ long train takes $10s$ to pass a man who is going in the same direction at the speed of $2kmph$. What is the speed of the train?

• A. $52kmph$
• B. $56kmph$
• C. $84kmph$
• D. Data inadequate

Answer 1

Answer: (B)

$56kmph$

Let the speed of the train be $xkmph$

Length of the train $=150m=\frac{150}{1000}=\frac{3}{20}km$
and time taken to cross the man = $10$ seconds = $\frac{10}{60\times 60}$
Relative speed = $(x-2)kmph$
(Both are moving in same direction)
We know that,
$\frac{\text{Length of the train}}{\text{Relative speed}}=$ Time taken to cross the man
Relative speed = $\frac{3\times 360}{20\times 1}$
$x-2=\frac{3\times 360}{20\times 1}$
$x=54+2=56kmph$
Hence, speed of train is $56kmph$.