SOLUTION: 2 cars start at an interstate and travels in the same direction at average speeds of 40 miles per hour and 55 miles per hour. How much time must elapse before the 2 cars are 5 mile

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: 2 cars start at an interstate and travels in the same direction at average speeds of 40 miles per hour and 55 miles per hour. How much time must elapse before the 2 cars are 5 mile      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 270193: 2 cars start at an interstate and travels in the same direction at average speeds of 40 miles per hour and 55 miles per hour. How much time must elapse before the 2 cars are 5 miles apart?
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
This is an RTD problem. Here is a table based on the given information.
cars. . . . . . . . .rate . . . . . . . .time . . . . . . . . . .distance
A. . . . . . . . . . . 40. . . . . . . . . .t. . . . . . . . . . . . . .40t
B . . . . . . . . . . .55. . . . . . . . . .t. . . . . . . . . . . . . .55t
totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Looking at column 3, we get
55t - 40t = 5
15t = 5
t = 1/3 hr
This is 20 minutes.