Solve the problem.
-An airplane leaves Los Angeles for Denver at a speed of 420 mph. Thirty minutes later, a plane going from Denver to Los Angeles leaves Denver, which is 850 miles from Los Angeles, at a speed
Of 520 mph. When they meet, how far are they from Denver?
A) 307 mi
B) 123 mi
C) 354 mi
D) 61 mi

Question

Quizplus · Accepted Answer

The first plane has a 30-minute head start, so it covers 420 mph * 0.5 hours = 210 miles before the second plane starts. The remaining distance when the second plane starts is 850 miles - 210 miles = 640 miles. The planes are closing in on each other at a combined speed of 420 mph + 520 mph = 940 mph. To cover the remaining 640 miles at 940 mph, it takes 640 miles / 940 mph = 0.68085 hours. In this time, the plane from Denver covers 520 mph * 0.68085 hours = 354 miles. Therefore, when they meet, they are 354 miles from Denver.

Solve the Problem. -An Airplane Leaves Los Angeles for Denver at a Speed