Felecia left her home to visit her daughter, driving 45mph. Her husband waited for the dog sitter to arrive and left home 20 minutes, or 13 hour later. He drove 55mph to catch up to Felecia. How long before he reaches her?

Step 1; Felecia is traveling at 45 mph, her husband starts 20 minutes after her but travels at a speed of 55 mph. So first we need to calculate how much of a head start Felecia got.

Head start = [tex]\frac{1}{3}[/tex] × 45 miles an hour = 15 miles.

So Felecia got a head start of 15 miles.

Step 2; Since Felecia and her husband are traveling at different rates, we can determine how much distance there is between them. Since Felecia is traveling at 45 mph and her husband is traveling at 55 mph, their gap in between is closing at a rate of 55 - 45 = 10 miles every hour. So for every hour, the gap between them is closing by 10 miles.

Total gap initially = 15 miles.

The rate at which gap is being closed = 10 miles an hour.

Time to close the gap = 15 / 10 = 1.5 hours.