Two planes left an airport at noon. One flew east at a certain speed and the other flew west at twice the speed. The planes were 2700 mi apart in 3 h. How fast was each plane flying?

1 Answer
Jan 20, 2016

If we call the speed of the first plane $v$ then the other plane has a speed of $2 \cdot v$

Explanation:

So the distance between the planes will get greater by
$v + 2 \cdot v = 3 \cdot v$ every hour
So in three hours their distance will be:
$3 \cdot 3 \cdot v$ which is equal to $2700 m i$

So $9 \cdot v = 2700 \to v = \frac{2700}{9} = 300 m p h$
And the other plane had twice that speed: $600 m p h$