Bob is 80 miles ahead of Joe Joe is traveling 70 miles per h

Bob is 80 miles ahead of Joe. Joe is traveling 70 miles per hour. Bob is traveling 55 miles per hour. how long will it take Joe to catch up?

Solution

speed of Joe = 70 miles per hr
speed of Bob = 55 miles per hour
since both are travelling in the same direction , relative speed = 70-55
= 15 miles per hour
already Bob, 80 miles ahead before start of joe
Joe has to cover 80 miles with relative speed
time = distance / speed
= 80 /15
=5.33 hours
= 5 hrs+0.33 hr (1 hr =60 min)
= 5 hr +0.33*60
=5 hr +20 min
Result : 5 hours 20 minutes