SOLUTION: an athlete runs at 9mph and then at 12 mph, covering 10 miles in 1 hour. how long did the athlete run at each speed?

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Question 119772This question is from textbook
: an athlete runs at 9mph and then at 12 mph, covering 10 miles in 1 hour. how long did the athlete run at each speed? This question is from textbook

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
9*X+12(1-X)=10
9X+12-12X=10
-3X=10-12
-3X=-2
X=-2/-3
X=2/3 OR 40 MINUTES FOR THE 9 MPH SEGMENT.
1-2/3=1/3 OR 20 MINUTES FOR THE 12 MPH SEGMENT.
PROOF
9*2/3+12*1/3=10
6+4=10
10=10