Solving Word Problems With Equations

• May 24th 2010, 02:34 PM
larry21
Solving Word Problems With Equations
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)
• May 24th 2010, 03:35 PM
TheEmptySet
Quote:

Originally Posted by larry21
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 $d=rt \iff t=\frac{d}{r}$

Let $r$ be the speed of the commuter plane then $2r$ is the speed of the jet then

$\frac{300}{r}+\frac{2000}{2r}=3.25$