SOLUTION: Carlos drives from Point-A to Point-B at an average speed of 36 miles per hour. He returns along the identical route at an average speed that is faster than 36 miles per hours. Whe

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Question 1166933: Carlos drives from Point-A to Point-B at an average speed of 36 miles per hour. He returns along the identical route at an average speed that is faster than 36 miles per hours. When he gets back (to Point-A), he realizes that his average speed for the overall roundtrip was 40 miles per hour. What was his average speed on the return trip (from Point-B to Point-A) ?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
             SPEED        TIME       DISTANCE

A to B       36           d/36          d

B to A       r            d/r           d

TOTALS               d/36+d/r          2d


Average speed for whole round trip, 40 mph.

%282d%29%2F%28d%2F36%2Bd%2Fr%29=40

highlight_green%282%2F%281%2F36%2B1%2Fr%29=40%29---------simplify and solve for r.