<PRE><B>Question 333792</B>
M drove to a friends house at 40 miles an hour, he returned the same route at 45 miles an hour.
 the driving time was 4 hours. what distance did he travel?
:
Let d = the one way distance
:
Write a time equation, Time = dist/speed
:
Time there + time back = 4 hrs
{{{d/40}}} + {{{d/45}}} = 4
Multiply equation by 360 to clear the denominators, results:
9d + 8d = 360(4)
17d = 1440
d = {{{1440/17}}}
d = 84.7 mi is the one way distance
then
2 * 84.7 = 169.4 miles traveled
;
:
Check solution by finding the time each way
84.7/40 = 2.1175 hrs
84.7/45 = 1.8822 hrs
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total time: 3.9997 ~ 4 hrs, confirmed our solution</PRE>