Solving Word Problems With Equations

May 2010
26
1
Another word problem.

David flew 300km on a commuter plane, then 2000km on a passenger jet. The passenger jet flew twice as fast as the commuter plane. The total flying time for the journey was 3.25 hours. What was the speed of each plane, in kilometers per hour?

Please help. I've been trying to tackle this problem for an hour+ and had no luck solving it.(Headbang)
 

TheEmptySet

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Feb 2008
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Another word problem.

David flew 300km on a commuter plane, then 2000km on a passenger jet. The passenger jet flew twice as fast as the commuter plane. The total flying time for the journey was 3.25 hours. What was the speed of each plane, in kilometers per hour?

Please help. I've been trying to tackle this problem for an hour+ and had no luck solving it.(Headbang)
Remember \(\displaystyle d=rt \iff t=\frac{d}{r}\)

Let \(\displaystyle r\) be the speed of the commuter plane then \(\displaystyle 2r\) is the speed of the jet then

\(\displaystyle \frac{300}{r}+\frac{2000}{2r}=3.25\)