Train and Sound

Think about it -> The train hears the second sound after 11 min instead of 12. This shows that the distance travelled by the train in 11 min is equal to the distance travelled by sound in 1 min 330 1 60 = v 11 60 Solve to get v = 30 m/sec or 108kmph

After hearing the first gunshot, the train traveled a distance $D$ in $11$ minutes before hearing the second gunshot. It should be noted that sound took $1$ minute to travel distance $D$ . Given that speed of sound $330$ $m/s$ . Therefore,

$D=330 \times 60\space m$

The train speed $v$ is:

$v=\cfrac{D}{11\times 60}=\cfrac{330\times 60}{11\times 60}=30 \space m/s = \cfrac{30 \times 60 \times 60}{1000}=\boxed{108}\space km/h$