Question

Two marathon runners start a race at different times. Runner A stars her race first. and then Runner B starts his race 30 minutes later. Runner A runs 4 miles per hour. Runner B runs 6 miles per hour. Which equation can be used to determine the time in hours, t, that the runners will be side by side, the same distance from the starting line?

Answer 1

4t = 6(t - 1/2)

Explanation:

For Runner A, the expression is 4t since this runner's rate is 4 mph. For Runner B, the expression is 6(t - 1/2) since Runner B starts 1/2 hour after Runner A, and this runner's rate is 6 mph. Set these two expressions equal to each other.