Question

A suspicious-looking man runs as fast as he can along a moving sidewalk from one end to the other, taking 2.50 s. Then security agents appear, and the man runs as fast as he can back along the sidewalk to his starting point, taking 13.0 s. What is the ratio of the man's running speed to the sidewalk's speed?

Answer 1

13:9 because he starts back then runs slower

Answer 2

Answer:

The ratio of the man's running speed to the sidewalk's speed: 5: 26.

Explanation:

Let the distance between the sidewalk from one end to the other be x

Distance covered by the man = x

Time taken by the person to cover x distance = 2.50 seconds

Speed of the man while running to other end point = S

$S=\frac{x}{2.50 s}$..[1]

Distance covered by the man by running back to his starting point after agents appears = x

Time taken by the person to cover x distance after agents appears = 13.0 seconds

Speed of the man while running back to starting point after agents appears = S'

$S'=\frac{x}{13.0 s}$...[2]

The ratio of the man's running speed to the sidewalk's speed:

[2] ÷ [1]

$\frac{S'}{S}=\frac{\frac{x}{13.0 s}}{\frac{x}{2.50 s}}=\frac{5}{26}$