Skip to main content

2008 AMC 10A Problem 1

Problem 1 of 25EasierAlgebra

A bakery owner turns on his doughnut machine at 8:308{:}30 am. At 11:1011{:}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

Show solution

Solution

From 8:308{:}30 am to 11:1011{:}10 am is 22 hours and 4040 minutes, or 160160 minutes, to finish one third of the job. The entire job therefore takes 3⋅160=4803 \cdot 160 = 480 minutes, or 88 hours. Eight hours after 8:308{:}30 am is 4:304{:}30 pm. Thus, the correct answer is D.

More practice

Concepts: date and time · ratio and proportion

Problem text and solution from the LIVE past-contest archive. See also the AoPS wiki page for community solutions.