SOLUTION: Beth had planned to run an average of 6 miles per hour in a race. She had a very good race and actually ran at an average speed of 7 miles per hour, finishing 10 minutes sooner tha

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Question 777658: Beth had planned to run an average of 6 miles per hour in a race. She had a very good race and actually ran at an average speed of 7 miles per hour, finishing 10 minutes sooner than she would have if she had averaged 6 miles per hour. How long was the race?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Beth had planned to run an average of 6 miles per hour in a race. She had a very good race and actually ran at an average speed of 7 miles per hour, finishing 10 minutes sooner than she would have if she had averaged 6 miles per hour. How long was the race?
time taken with speed of 6 mph - time taken with speed of 7 mph =10minutes
t=d/r
let x be the distance of the race
time = x/6 ( planned)
(x/7) = actual time
x%2F6-x%2F7=10%2F60
x%2F6-x%2F7+=+1%2F6
Multiply equation by 42
%28x%2A42%29%2F6+-%28x%2A42%29%2F7+=42%2F6
7x-6x=7
x=7=> distance