Question

An express train 180 meters with a speed of 72 km/h. In what time will it pass an electric pole ?

Answer 1

$72$ km $\to 1$hr

$72000$m $\to 1$ hr

$180$m $\to \frac{1}{72000}\times 180$ hr

$=\frac{180\times 60\times 60}{72000}$ seconds

$=9$ seconds.