SOLUTION: 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?

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?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
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
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