<PRE><B>Question 988059</B>
If a plane travels 450 mph from LAX to JFK airports one way and travels 500 mph back
 how many miles did the plane travel if it took 13.3 hours for the round trip? 
:
let d = the one-way dist from LAX to JFK
Write a time equation; time = dist/speed
 to time + return time = 13.3 hrs
{{{d/450}}} + {{{d/500}}} = 13.3
multiply equation by the least common multiple of 450 and 500, 
4500*{{{d/450}}} + 4500*{{{d/500}}} = 4500(13.3)
Cancel the denominators and you have
10d + 9d = 59850
19d = 59850
d = 59850/19
d = 3150 mi is the one way distance
therefore
2 * 3150 = 6300 mi traveled in the round trip
:
:
Confirm this by finding the actual time each way
3150/450 = 7.0 hrs
3150/500 = 6.3 hrs
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total time: 13.3 hrs</PRE>