SOLUTION: Kyle rode his bike for 12 miles. During the first third of the trip, he traveled on level ground at an average rate of 10 mph. During the second third of the trip, he traveled uphi

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Question 1138509: Kyle rode his bike for 12 miles. During the first third of the trip, he traveled on level ground at an average rate of 10 mph. During the second third of the trip, he traveled uphill at an average rate of 6 mph. During his last third of the distance, he traveled downhill at an average rate of 15 mph. How long did Kyle's 2-mile bike trip take?
Answer by ikleyn(52797) About Me  (Show Source):
You can put this solution on YOUR website!
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Kyle spent  4%2F10  of an hour on the level ground part of the length 4 = 12%2F3 miles.


Then he spent  4%2F6 = 2%2F3  of an hour on the uphill part of the same length 4 = 12%2F3 miles.


Finally, he spent  4%2F15 of an hour on the downhill part of the same length 4 = 12%2F3 miles.


In all, he spent  4%2F10+%2B+2%2F3+%2B+4%2F15 = 12%2F30+%2B+20%2F30+%2B+8%2F30 = 40%2F30 = 4%2F3 hours for the entire 12-miles trip.


ANSWER.  His trip took  4%2F3 hours = 11%2F3 hours = 1 hour and 20 minutes.