Question 78226
Russ and Janet are running in the Apple Hill Fun Run. Russ runs at 7 mph, Janet at 5 mph. If they start at the same time, how long will it be before they are 1/2 miles apart?
:
Let t = required time for them to be 1/2 mile apart
:
Write a distance equation: dist = speed * time
:
Rus's dist - Jan's dist = 1/2 mile
7t - 5t = 1/2
:
2t = 1/2
:
4t = 1; multiplied by 2, gets rid of the denominator
:
t = 1/4 of an hr:  In 15 min they will be 1/2 mile apart
:
:
Check: 
7(1/4) - 5(1/4) =
7/4 - 5/4 = 2/4 = 1/2 mile