Question

mary has an essay due in 4 days. she estimates that she needs to spend 6 hours working on her essay. she wants to split up the work and work the same amount of time each day. mary goes to bed at 10:00 p.m. and plans to work on her essay right before she goes to sleep. what time should mary start working on her essay each night so she can complete her essay on time?
8:00 p.m.
9:30 p.m.
9:00 p.m.
8:30 p.m

Explanation:

Step1: Calculate daily work time

Mary needs 6 hours total over 4 days, so daily time is $6\div4 = 1.5$ hours (or 1 hour 30 minutes).

Step2: Find start time

She goes to bed at 10:00 p.m. Subtract 1.5 hours from 10:00 p.m. 10:00 p.m. minus 1 hour is 9:00 p.m., minus 30 minutes is 8:30 p.m.? Wait, no—wait, 10:00 p.m. minus 1.5 hours: 1.5 hours is 1 hour 30 minutes. So 10 - 1 = 9, then 9 - 0.5 (30 minutes) = 8:30? Wait, no, wait: if she works 1.5 hours before 10, start time is 10 - 1.5 = 8.5, which is 8:30 p.m.? Wait, no, wait, maybe I messed up. Wait, 6 hours over 4 days: 6/4 = 1.5 hours per day. So each day she works 1.5 hours. So start time = 10:00 p.m. - 1.5 hours. 10:00 p.m. minus 1 hour is 9:00 p.m., minus 30 minutes is 8:30 p.m.? Wait, no, 1.5 hours is 90 minutes. 10:00 p.m. is 22:00. 22:00 - 1:30 = 20:30, which is 8:30 p.m. Wait, but let's check again. Wait, maybe the options: the options are 8:00, 9:30, 9:00, 8:30. Wait, maybe I made a mistake. Wait, 6 hours total, 4 days: 6/4 = 1.5 hours per day. So each day she works 1.5 hours. So start time is 10:00 p.m. minus 1.5 hours. 10 - 1.5 = 8.5, which is 8:30 p.m. So the correct option is 8:30 p.m. Wait, but let's re-express: 10:00 p.m. minus 1 hour 30 minutes. 10:00 - 1 hour = 9:00, then -30 minutes = 8:30. Yes. So the start time is 8:30 p.m.

Answer:

8:30 p.m. (the option with 8:30 p.m.)