SOLUTION: Carlos drove to his cabin on the lake and back. The trip there took four hours and the trip back took 1.6 hours. He averaged 37.5 km/h faster on his return trip than on his outboun

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Carlos drove to his cabin on the lake and back. The trip there took four hours and the trip back took 1.6 hours. He averaged 37.5 km/h faster on his return trip than on his outboun      Log On

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Question 831323: Carlos drove to his cabin on the lake and back. The trip there took four hours and the trip back took 1.6 hours. He averaged 37.5 km/h faster on his return trip than on his outbound trip. Find carlos' average speed on the outbound trip.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ km = the one-way distance he travels
Let +s+ km/hr = his speed on the outbound trip
+s+%2B+37.5+ km/hr = his speed on the return trip
----------------------
Equation for outbound trip:
(1) +d+=+s%2A4+
Equation for return trip:
(2) +d+=+%28+s%2B37.5+%29%2A1.6+
-------------------------
+4s+=+1.6s+%2B+60+
+2.4s+=+60+
+s+=+25+
The average speed for the outbound trip is 25 km/hr
check:
(1) +d+=+25%2A4+
(1) +d+=+100+
and
(2) +d+=+%28+s%2B37.5+%29%2A1.6+
(2) +d+=+%28+25+%2B+37.5+%29%2A1.6+
(2) +d+=+62.5%2A1.6+
(2) +d+=+100+
OK