Bob left home, riding his bike at a rate of 10mph to go to the lake. Cheryl, his wife, left 45 minutes later, driving her car at a rate of 25mph. How long will it take Cheryl to catch up to Bob?

Answer 1

Bob goes 10mph for 3/4 hours or he travels 30/4 miles

Cheryl starts at time = 0 at 25 mph.

So, for both starting at time = 0

30/4 miles + 10t = 25t or 15t = 30/4 or t = 2/4 = 1/2 hour

So, it takes Cheryl 30 minutes to catch Bob!