SOLUTION: How far away can a boy ride his bike if he rides away at 10 kilometers per hour and returns at 9 kilometers per hour? The entire trip takes 9.5 hours.

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Question 594771: How far away can a boy ride his bike if he rides away at 10 kilometers per hour and returns at 9 kilometers per hour? The entire trip takes 9.5 hours.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
How far away can a boy ride his bike if he rides away at 10 kilometers per hour and returns at 9 kilometers per hour? The entire trip takes 9.5 hours.
:
Let d = one-way distance the boy went.
:
Write a time equation: time = dist/speed
;
go time + return time = 9.5 hrs
d%2F10 + d%2F9 = 9.5
multiply by 90 to clear the denominators
90*d%2F10 + 90*d%2F9 = 90(9.5)
Cancel the denominators
9d + 10d = 855
19d = 855
d = 855%2F19
d = 45 km
:
:
Check this by finding the actual time for each way:
45/10 = 4.5 hrs
45/9 = 5 hrs
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total: 9.5 hrs