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

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Question 465935: How far away can a boy ride his bicycle if he rides away at 10 kilometeres per hour and returns at 9 kilometers per hour? the entire trip takes 9.5 hours
Found 2 solutions by jorel1380, robertb:
Answer by jorel1380(3719) About Me  (Show Source):
You can put this solution on YOUR website!
x/10+x/9=9.5
9x+10x=855
19x=855
x=45
The boy rode 45 kilometers each way.

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Get the average speed of the boy in the entire trip by taking the harmonic mean of the rates:
2%2F%281%2F10+%2B+1%2F9%29+=+180%2F19 kph.
Multiplying this average rate by 9.5 hr, we get 90 kilometers. This is the distance traveled in the ROUND TRIP, so to get the one-way distance, divide by 2.
Hence the boy can ride his bike up to 45 km.