Question

The time taken by 150 m long train running at a speed of 72 km/hr to pass a bridge is 12.5 s. The length of the bridge is.

• A. 100 m
• B. 90 m
• C. 120 m

Answer 1

The correct option is A 100 m

$\text{Length of the train}=150m\text{Let length of the bridge}=xm\text{Time taken =}12.5s$

$\text{Speed of train}=72\text{km/hr}=72\times \frac{5}{18}=20\text{m/s}$

In order to cross the bridge,the train travels a total distance of
$(150+x)m.$

$\text{We know that,}\text{Distance = Speed}\times \text{Time}150+x=20\times 12.5150+x=250\text{m}x=100\text{m}$