A baby goes to sleep at 8 p.m., wakes up after two hours, stays awake for 15 minutes, and then goes back to sleep. If the baby repeats this sleep pattern until she is awakened at 6 a.m., what percent of the time from 8 p.m. to 6 a.m. was the baby asleep?
+128473 We have 10 hours between 8PM and 6AM = 10 * 60 = 600 minutes
Sleep 8 -10
Awake 10 - 10:15
Sleep 10:15 - 12:15
Awake 12:15 - 12:30
Sleep 12:30 - 2:30
Awake 2:30 - 2:45
Sleep 2:45 - 4:45
Awake 4:45 - 5
Sleep 5 - 6
There are 4 periods of 2 hour sleep and 1 period of 1 hour sleep = 4*2(60) + 1(60) = 480 + 60 = 540 minutes asleep
So 540/600 = 54/60 = 9/10 = 90% of the time asleep
