Answer:
257.5 mph
332.5 mph
Step-by-step explanation:
The initial distance between the two planes is 960 miles, while the final distance (after t=1.5 h) is 75 miles, so the total distance covered by the two planes in 1.5h is
miles
Calling v1 and v2 the velocities of the two planes, we have the following equations:
(1) --> velocity of plane 1 exceeds velocity of plane 2 by 75 mph
(2) --> the total distance covered by the two planes is 885 miles (t=1.5 h is the time, and the products v1 t and v2 t represent the distance covered by each plane)
Substituting t=1.5 h, the second equation becomes:
By substituting (1) into this last equation, we find:
And substituting this back into eq.(1), we find
So, the speeds of the two planes are
257.5 mph
332.5 mph