SOLUTION: A cyclist rides D km at a rate of X km/hr and returns D km at a rate of Y km/hr. Write an expression representing the average rate in terms of X,Y and D. Simplify this expression
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Question 103550: A cyclist rides D km at a rate of X km/hr and returns D km at a rate of Y km/hr. Write an expression representing the average rate in terms of X,Y and D. Simplify this expression if you can.
rate=distance/time
Total distance = 2D
rate=Total Distance/Total Time
I can't figure out how to get the total time in terms of X and Y. Can you help?
Thanks!
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A cyclist rides D km at a rate of X km/hr and returns D km at a rate of Y km/hr. Write an expression representing the average rate in terms of X,Y and D. Simplify this expression if you can.
---------------------
1st ride DATA;
Rate = X km/h ; Distance = D miles ; Time = D/R = D/X hrs
----------------
Return ride DATA:
Rate = Y km/h ; Distance = D miles ; Time = D/R = D/Y hrs
------------------
Average Rate = (total distance) / (total time) = 2D/[D/X + D/Y]
= 2D/[D(Y+X)/XY]
= 2XY/(X+Y)
=================
Cheers,
Stan H.
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