algebra
posted by Nabil .
two buses leave at the same time.
one travels west at 40 mph.
the other goes north at 30 mph.
When will they be 400 miles apart?

(30t)^2 + (40t)^2 = 400^2

30t+40t=400
70t=400
t= 400/70
=5.71hrs
After 5.71hrs they will be at 400miles apart. 
Deez N***