Question

Ben starts walking along a path at 3 mi/h. One and a half hours after Ben leaves, his sister Amanda begins jogging along the same path at 7 mi/h. How long (in hours) will it be before Amanda catches up to Ben?

Enter the exact answer.
Hint: The distance formula is that distance = rate * time, so for example in one and a half hours, Ben has walked 3 * 1.5 miles.

Amanda catches up to Ben in ____________ hours.

Answer 1

1.125 hours

Explanation:

Given :

Ben's speed = 3 mi/hr

Time before Amanda starts = 1.5 hours

Amanda's speed = 7 mi/hr

Time before Amanda catches up with Ben

Recall :

Distance = speed * time

Distance already covered by Ben before Amanda starts :

(3 * 1.5) = 4.5

Hence, we can setup the equation :

Ben's distance = Amanda's distance

Let time taken = x

4.5 + 3x = 7x

4.5 = 7x - 3x

4.5 = 4x

x = 4.5 / 4

x = 1.125 hours

1.125 * 60 = 67. 5 minutes