Posted by thommini on .
If two planes leave the same airport at 1:00 PM, how many miles apart will they be at 3:00 PM if one travels directly north at 150 mph and the other travels directly west at 200 mph? ( please help me with the working thanks )

maths 
drwls,
When you add a westfacing vector of length 200 t and a northfacing vector of length 150 t, the resultant displacement, which is the hypotenuse, will have a length of 250 t. This is becasue the sides of the right triangle are always in a 3:4:5 ratio.
(250t)^2 = (150t)^2+ (200t)^2
After t = 2 hours, they will be d = 500 miles apart, since
d^2 = sqrt[{300)^2 + (400)^2)]