Question 1100086
1. Mary departs for school on a bicycle at an average rate of 6 miles per hour.
 Her sister Kate, running late, leaves 15 minutes later and cycles at twice that speed.
 How long will it take Kate to catch Mary?
:
We are dealing in mph, change 15 min to .25 hrs
let t = Kate's travel time
then
(t+.25) = Mary's travel time
:
When K catches M, they will have traveled the same distance
Write a distance equation, dist = speed * time
12t = 6(t+.25)
12t = 6t + 1.5
12t - 6t = 1.5
6t = 1.5
t = 1.5/6
t = .25 hrs or 15 min for K to catch M