Question

Two trains, each 880 yd long, are running in opposite directions on parallel tracks. Their speeds are 56 mph and 34 mph, respectively. Find the time taken by the slower train to pass the driver of the faster one. ($\text{1 mph}=\frac{1760}{3600}yd/s$)

• A. 24 s
• B. 20 s
• C. 44 s
• D. 22 s

Answer 1

The correct option is B 20 s

$\text{Speed of the faster train}=56\text{mph}$

$\text{Speed of the slower train}=34\text{mph}$

$\text{Let's find the relative speed of both the trains}$
$\text{because they are traveling in opposite}$
$\text{directions.}$

$\text{Relative speed}$
$=\text{Sum of speed (faster + slower) train}$

$⟹(56+34)\text{mph}$

$⟹(90\times \frac{1760}{3600})\text{yd/s}$

$⟹(90\times \frac{22}{45})\text{yd/s}$

$⟹44\text{yd/s}$

We have to find the time taken by the slower train to pass the driver of the faster train and not the complete train.

So,
Distance covered = Length of the slower train

Therefore,
Distance covered = 880 yd

We know,
$\text{Time}=\frac{\text{Distance}}{\text{Speed}}$

$=\frac{880}{44}$

$=20\text{s}$