9.) At 10:30 a.m. two planes leave Houston, one flying east at 560 km/h and the other flying west at 640 km/h. at what time will they be 2100 km apart?

Question

mertsj · Answer

The distance of the first plane is 560t 
The distance of the second plane is 640t
 The sum of the two distances must be 2100 
Write and solve that equation.

anonymous · Answer

The two planes leave at the same time in opposite directions, so velocity (v) of PLane A =560, velocity of plane B = -640. Their total velocity is 560+640 km /h = 1200 km/h.

So after one hour the two planes are 1200 km apart from each other. Setup an equation for when they get to 2100 km apart.