<PRE><B>Question 955943</B>
Elizabeth drove half the distance of a trip at 35 mph. At what speed would she have to drive for the rest of the distance so that the average speed for the entire trip would be 52 mph?
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d = 1/2 the total distance
r = speed of the 2nd half
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d/35 + d/r = 2d/52
1/35 + 1/r = 1/26
(r + 35)/35r = 1/26
r+35 = 35r/26
26r + 910 = 35r
9r = 910
r = 101.111...  mi/hr
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