# Flying Speeds

• Mar 30th 2008, 05:45 AM
sniderman
Flying Speeds
Two planes leave Pittsburgh and Philadelphia at the same time, each going to the other city. One plane flies 25 miles per hour faster than the other. Find the air speed of each plane if the cities are 275 miles apart and the planes pass each other after 40 minutes of flying time.
• Mar 30th 2008, 07:49 AM
Soroban
Hello, sniderman!

Will use: .$\displaystyle \text{Distance}\;=\;\text{Speed} \times \text{Time}$

Quote:

Two planes leave Pittsburgh and Philadelphia at the same time, each going
to the other city. One plane flies 25 miles per hour faster than the other.
Find the air speed of each plane if the cities are 275 miles apart
and the planes pass each other after 40 minutes of flying time.

Let $\displaystyle x$ = one plane's speed.
Then $\displaystyle x + 25$ = other plane's speed.

In $\displaystyle \frac{2}{3}$ of an hour, the first plane flies: .$\displaystyle \frac{2}{3}x$ miles.

In $\displaystyle \frac{2}{3}$ of an hour, the other plane flies: .$\displaystyle \frac{2}{3}(x+25)$ miles.

Together, they cover the 275 miles.

There is our equation . . . . . $\displaystyle \frac{2}{3}x + \frac{2}{3}(x + 25) \;=\;275$

. . Go for it!