Problem:
A bakery owner turns on his doughnut machine at 8:30 Am. At 11:10 AM the machine has completed one third of the day's job. At what time will the doughnut machine complete the job?
Answer Choices:
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Solution:
The machine worked for 2 hours and 40 minutes, or 160 minutes, to complete one third of the job, so the entire job will take minutes, or 8 hours. Hence the doughnut machine will complete the job at .
The problems on this page are the property of the MAA's American Mathematics Competitions