Question

Alyssa can complete a job in 12 minutes. If Miranda helps her, they can complete the job in 9 minutes. How long would it take Miranda to complete the job by herself? (In minutes.) Rate of work problem

Answer 1

36 minutes

Explanation:

The key is to get the same amount of time for each.

9 * 12 = 108

At 12 minutes per job,

in 108 minutes Alyssa could do

108/12 = 9 jobs

At 9 minutes per job,

Together in 108 minutes they could do

108/9 = 12 jobs

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In 108 minutes Mirada does

12 - 9 = 3 jobs

108/3 = 36 minutes per job