Sheila leaves on a trip driving at 30 miles per hour. Two hours later, her sister Allison leaves from the same location driving at 45 miles per hour. How long after Allison leaves home will she catch up to Sheila?

Question

Sheila leaves on a trip driving at 30 miles per hour. Two hours later, her sister Allison leaves from the same location driving at 45 miles per hour. How long after Allison leaves home will she catch up to Sheila?

6 hours

2 hours

4 hours

5 hours

Answer 1

4 hours

Explanation:
After 2 hours, Sheila has traveled 60 miles (30mph x 2 hours = 60 miles).
Allison is now 60 miles behind Sheila.
Allison drives 15mph faster than Sheila, so she will catch up at a rate of 15mph.
It will take Allison 4 hours (60 miles ÷ 15mph = 4 hours) to catch up to Sheila.