Question

john is walking east at a speed of 3 miles per hour, while bob is also walking east, but at a speed of 5 miles per hour. if bob is now 1 mile west of john, how many minutes will it take for bob to catch up to john?

Answer 1

30 minutes

Explanation:

You want to know the number of minutes it will take Bob, who is starting 1 mile behind John, to catch up to John if Bob and John are walking the same direction at 5 mph and 3 mph, respectively.

Time

The distance that needs to be closed between the two walkers is 1 mile. The difference in their walking speeds is 5 -3 = 2 mph. This means the distance will be closed in ...

(1 mi)/(2 mi/h) = 1/2 h = 30 minutes

It will take 30 minutes for Bob to catch up to John.

__

Additional comment

We can graph their locations east of where John starts. The graphs of their positions intersect at (hours, miles) = (0.5, 1.5). That is, Bob will cover 2.5 miles in the 1/2 hour it takes him to catch John, who will have covered 1.5 miles in that time.

<95141404393>