Question

Two trains, $130$ and $110$ metres long are going in the same direction. The faster train takes one minute to pass the other completely. If they are moving in opposite directions, then they pass each other completely in $3$ seconds. Find the speed of the faster train.

• A. $38$ m/sec
• B. $42$ m/sec
• C. $46$ m/sec
• D. $50$ m/sec

Answer 1

The correct option is B $42$ m/sec

Let the speed of faster and slower trains be $x$ m/sec and $y$ m/sec respectively. Then
$\frac{240}{x-y}=60$
$\Rightarrow x-y=4\cdots \left(i\right)$
And $\frac{240}{x+y}=3$
$\Rightarrow x+y=80\cdots \left(ii\right)$

Adding $\left(i\right)$ and $\left(ii\right),$ we get
$2x=84$
$\Rightarrow x=42$
Putting $x=42$ in equation $\left(i\right),$ we get $y=38$
Hence, speed of faster train $=42$ m/sec.