Question

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

Answer 1

Alright, so he went the same distance there and back, but at different speeds

hmm

d=st
d/s=t

total time is 9.5hr

alright

so distance there=distance back we will call both of them d

so

speed there is 10
speed back is 9
total time is 9.5

so
d/sthere+d/sback=totaltime
d/10+d/9=9.5
times both sides by 90
9d+10d=855
19d=855
divide both sides by 19
d=45

he can ride 45mi away