Question

A suspicious-looking man runs as fast as he can along a moving sidewalk from one end to the other, taking 2.10 s. Then security agents appear, and the man runs as fast as he can back along the sidewalk to his starting point, taking 13.2 s. What is the ratio of the man's running speed to the sidewalk's speed?

Answer 1

Answer:1.37

Explanation:

Given

Man run along the side walk and take 2.1 s

While walking in the opposite direction it takes 13.2 s

Let the speed of man and sidewalk be $v & v_s$

Let the distance between two points be x

$x=(v+v_s)2.1 ------1$

$x=(v-v_s)13.2-----2$

From 1 & 2 we can get

$2.1v+2.1v_s=13.2v-13.2v_s$

$15.3v_s=11.1v$

$\frac{v}{v_s}=\frac{15.3}{11.1}=1.37$