SOLUTION: over a distance a car traveling 40 mph, the car then drives that same distance 10 mph, what is the average mph for the whole trip? i tried working it out but i got stuck at the 2nd
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Question 654675: over a distance a car traveling 40 mph, the car then drives that same distance 10 mph, what is the average mph for the whole trip? i tried working it out but i got stuck at the 2nd stage of the solution so please give me a very detailed solution Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! over a distance a car traveling 40 mph,
the car then drives that same distance 10 mph,
what is the average mph for the whole trip?
:
let d = the distance traveled at 40 mph and the distance traveled at 10 mph
let a = the average mph for the trip
:
Write a time equation; time = dist/speed
:
40mph time + 10mph time = total time + =
multiply by 40a, to clear the denominators
40a* + 40a* = 40a*
Cancel the denominators
ad + 4ad = 40(2d)
5ad = 80d
divide both sides by d
5a = 80
a = 80/5
a = 16 mph is the average for the trip
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