Peggy sleeps \(7 \frac{1}{2}\) hours at night. Her clock radio is set for 6:15 A.M. At what time does she fall asleep?
Explanation
6:15 A.M. is \(6 \frac{1}{4}\)hours after midnight. To get \(7 \frac{1}{2}\) hours of sleep, she must have gone to sleep before midnight. To find how many hours before midnight she went to sleep, subtract.
\(7 \frac{1}{2} - 6 \frac{1}{4}=7 \frac{2}{4} - 6 \frac{1}{4} = \frac{1}{4}\)
Peggy went to sleep \(1\frac{1}{4}\) hours, or 1 hour and 15 minutes, before midnight. This means she fell asleep at 10:45 P.M.