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 miles per hour. During the second third of the trip, he tr

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Question 895220: 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 miles per hour. During the second third of the trip, he traveled uphill at an average rate of 6 miles per hour. During his last third of the distance, kyle traveled downhill at an average rate of 15 miles per hour. How long did kyle's 12-mile bike trip take?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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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 miles per hour.
During the second third of the trip, he traveled uphill at an average rate of 6 miles per hour.
During his last third of the distance, kyle traveled downhill at an average rate of 15 miles per hour.
How long did kyle's 12-mile bike trip take?
:
4 mi is 1/3 of the trip, so we have a simple time equation;
time = dist/speed
:
t = 4%2F10 + 4%2F6 + 4%2F15
convert of common denominator, 30
t = 12%2F30 + 20%2F30 + 8%2F30
t = 40%2F30 = 4%2F3 hr = 1 hr 20 min