Answer:
2:15 pm
Explanation:
The time that Theo finishes is the sum of the start time and the duration of the cleaning. The duration is the sum of the cleaning times for each of the rooms and the break time.
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sum of minutes
It is convenient to convert all of the times to minutes, then convert the total back to hours and minutes.
kitchen +lounge +bedroom +bathroom +breaks
= (60 +50) +(55) +(1/2×60) +(35) +(85)
= 110 +55 +30 +35 +85
= 315 . . . . minutes
minutes and hours
There are 60 minutes in an hour, so the sum is ...
(315/60) hours = 5 15/60 hours = 5:15 . . . . written as hours : minutes
Then the time Theo finishes is ...
9:00 +5:15 = 14:15 = 2:15 pm
Theo will finish cleaning at 2:15 pm.
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Additional comment
On a 24-hour clock, hours after noon are numbered 13, 14, 15, ... to 23 at 11 pm. The 12-hour representation of the pm hours can be found by subtracting 12 from the hour number.