a boat traveled upstream a distance of 90 miles

[ag4451]

A boat traveled upstream a distance of 90 miles at an average speed of (v-3) miles per hour and then traveled the same distance downstream at an average speed of (v+3) miles per hour. IF the trip upstream took half an hour longer than the trip downstream, how many hours did it take the boat to travel downstream?


2.5
2.4
2.3
2.2
2.1


I know the Answer but do not know why it is right.
Any help will be much appreciated.
The right answer is 2.5, but why?


Thanks,
Gupta

[RonPurewal]

A boat traveled upstream a distance of 90 miles at an average speed of (v-3) miles per hour and then traveled the same distance downstream at an average speed of (v+3) miles per hour. IF the trip upstream took half an hour longer than the trip downstream, how many hours did it take the boat to travel downstream?


2.5
2.4
2.3
2.2
2.1


I know the Answer but do not know why it is right.
Any help will be much appreciated.
The right answer is 2.5, but why?


Thanks,
Gupta

Please search the forum, thanks.

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