Question

Two cars leave the same location traveling in opposite directions. One car leaves at 3:00 p.m. traveling at an average rate of 55 miles per hour. The other car leaves at 4:00 p.m. traveling at an average rate of 75 miles per hour. Let x represent the number of hours after the first car leaves. How many hours after the first car leaves will the two cars be 380 miles apart?

Enter an equation that can be used to solve this problem in the first box. Solve for x and enter the number of hours in the second box.

Equation:
x =

Answer 1

x = hours

car 1 left an hour before car 2 so you have 55(x+1)

car 2 = 75x

 add them together to equal miles driven:

55(x+1) + 75x = 380

55x+55 + 75x = 380

 combine like terms:

130x+55 = 380

 subtract 55 from each side:

130x = 325

divide both sides by 130

x = 325 /130 = 2.5

x = 2.5 hours

 so 2.5 hours