SOLUTION: A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to pick up a load of freight. On the return trip (with the truck fully loaded), the average spee

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Question 1023982: A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to pick up a load of freight. On the return trip (with the truck fully loaded), the average speed was 35 miles per hour. Find the average speed for the round trip.
Found 3 solutions by josgarithmetic, Alan3354, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
               rate          time            distance

GOING          64                              200


RETURN         35                              200


Totals                                         400


RT=D relates rate, time, and distance. You need to fill-in the time cells in the table. 
               rate          time            distance

GOING          64            200/64            200


RETURN         35           200/35             200


Totals                  200%2F64%2B200%2F35           400

The average round-trip rate, before any simplifications, is 400%2F%28200%2F64%2B200%2F35%29;
and you will want to simplify this.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to pick up a load of freight. On the return trip (with the truck fully loaded), the average speed was 35 miles per hour. Find the average speed for the round trip.
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Avg speed of a round trip:
avg = 2*64*35/(64+35) = 4480/99 mi/hr
=~ 45.25 mi/hr
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Notice the distance is not relevant.

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to pick up a load of freight.
On the return trip (with the truck fully loaded), the average speed was 35 miles per hour. Find the average speed for the round trip.
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See the lesson Calculating an average speed: a train going from A to B and back in this site.

You will find the detailed solutions of similar problems there (Problems 1 and 2).