# How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?

A. 40 sec
B. 39 sec
C. 30 sec
D. 20 sec

Solution:

$\left. \begin{array} { l } { \text { Speed of the train relative to man: } }\\{= ( 63 – 3 ) km / hr } \\{ = 60 km / hr }\\{= ( 60 \times \frac { 5 } { 18 } ) m / se } \\ { = ( \frac { 50 } { 3 } ) m / sec } \\ { \therefore \text { Time taken to pass the man: } }\\{=( 500 \times \frac { 3 } { 50 } ) sec } \\ { = 30 sec . } \end{array} \right.$