Answer:
The speed of the car is 50 mph.
The speed of the plane is 150 mph.
Driving time = 185/50 = 3.7 hours
Flying time = 645/150 = 4.3 hours
Step-by-step explanation:
R be the speed of the car.
t is the driving time.
185 = R* t
645 = (3R)*(8-t) <--- the plane is 3 times as fast; the total time is 8 hours, so 8-t hours is spent flying
645 = 24R - 3rt <--- distributive
645 = 24R - 3(185) <--- substitutes rt = 185
645 = 24R - 555
1200 = 24R
R = 50
