Abus and a car leave from the same city traveling in opposite directions. the bus leaves 2 hours before the car does. the bus travels at a steady speed of 50 mph while the car travels at 70 mph. after how many hours will the bus and car be 800 miles apart?
if h represents the number of hours the bus travels, then which of the following expressions represents the number of miles the car travels?
70(h + 2)
70(h - 2)
70h

After 7.8 hours (7 hours 48 min.) will the bus and car be 800 miles apart

70(h-2) expression represents the number of miles the car travels.

Step-by-step explanation:

If h represents the number of hours the bus travels.

In the question it is said that the bus leaves 2 hours before the car does

Therefore car travels (Time) = ( h-2 )

car's speed = 70 mph,

Distance = speed × time = 70(h-2)

70(h - 2) expression represents the number of miles the car travels.

If we want to find the number of hours will the bus and car be 800 miles apart we can solve it as :

50h + 70(h-2) = 800

50h + 70h - 140 = 800

120h = 800 + 140

120h = 940

h = 940 ÷ 120 = 7.833... = 7.8 hours (7 hours and 48 min.)

Ans. After the bus left the city, after 7.8 hours the car and the bus will be 800 miles apart.

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer