Sara walked to the store in 15.7 minutes. She bought Band-AIDS for $0.55, gauze for $1.29 and suntan lotion for $2.89. She gave the clerk a $10 bill. She left the store at 3:45 a.m. It took her 19.2 minutes to walk home. How much longer did it take her to walk home than it took to walk to the store?