Question

A man sitting in a train which is traveling at $50$ kmph observes that a goods train, traveling in opposite direction, takes $9$ seconds to pass him. If the goods train is $280$ m long, then the speed of goods train is

• A. $68$ kmph
• B. $62$ kmph
• C. $92$ kmph
• D. $72$ kmph

Answer 1

The correct option is B $62$ kmph

Speed of goods train with respect to man $=\frac{280}{9}$ m / sec $=\frac{280}{9}\times \frac{18}{5}$ kmph $=112$ kmph.

Speed of goods train with respect to man $=$ speed of man $+$ speed of goods train
$\Rightarrow 112=50+$ speed of goods train
$\Rightarrow$ Speed of goods train $=(112-50)$ kmph $=62$ kmph.