Answer: The speed of the truck is 30 mph.
The speed of the car is 50 mph.
Step-by-step explanation:
Let x represent the speed of the car. If the trucks rate is 20 miles per hour slower than the car's, it means that the speed of the truck is
(x - 20) miles per hour.
Time = distance/speed
The truck can travel 210 miles in the same time it takes the car to travel 350 miles. It means that the time it would take the truck to travel 210 miles is
210/(x - 20)
Also, the time it would take the car to travel 350 miles is
350/x
Since the time is the same, it means that
210/(x - 20) = 350/x
Cross multiplying, it becomes
350(x - 20) = 210x
350x - 7000 = 210x
350x - 210x = 7000
140x = 7000
x = 7000/140
x = 50
The speed of the truck is
x - 20 = 50 - 20 = 30 mph
