How long will it take the officer to catch the thief?

Question

A police officer is chasing a purse-snatcher down a street. The thief starts 9 meters ahead of the officer and can run 20 meters in 4 seconds(5 meters per second). The police officer can run 32 meters in 4 seconds(8 meters per second)

Answer 1

Vanessa:

The cop approaches the thief at a net speed o (8 - 5) = 3 m/s

Since the thief starts 9 m ahead, we must find how long it take the cop to cover 9 m @ 3/ m/s

The general formula for this is: s = d/t where s= speed (m/s); d = distance (meters); and t = time (secs)

Rearranging: t = d/s

= 9 / 3

= 3 seconds

That's it!