SOLUTION: Ashley's family lives 240 miles away from Washington, DC. While visiting Washington, DC, they drove half of the distance with the speed 60 mph. Their speed during the remaining par

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Question 1006446: Ashley's family lives 240 miles away from Washington, DC. While visiting Washington, DC, they drove half of the distance with the speed 60 mph. Their speed during the remaining part of the trip was only 40 mph. On the way back home their speed was the same all the time, and the way back home took as much time as the way to Washington. What was their speed on the way back?
I don't get how to do this problem
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The family drove 120 mi at 60 mi/hr and
120 mi at 40 mi/hr going to DC
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Use +t+=+d%2Fs+ to find the times
+d%5B1%5D+=+120+
+s%5B1%5D+=+60+
+t%5B1%5D+=+d%5B1%5D+%2F+s%5B1%5D+
+t%5B1%5D+=+120%2F+60+
+t%5B1%5D+=+2+ hrs
-------------------
+d%5B2%5D+=+120+
+s%5B2%5D+=+40+
+t%5B2%5D+=+d%5B2%5D+%2F+s%5B2%5D+
+t%5B2%5D+=+120+%2F+40+
+t%5B2%5D+=+3+ hrs
-------------------
+t%5B1%5D+%2B+t%5B2%5D+=+5+ hrs
Let +s+ = their speed on the way back
use:
+s+=+d%2Ft+
+s+=+240+%2F+5+
+s+=+48+
Their speed going back was 48 mi/hr