Question

lea and marie are washing all the windows in their house. it would take lea 80 minutes to wash the windows by herself, and it would take marie 60 minutes to wash them by herself. lea creates a table so she can find out how long it will take to wash the windows if they work together. what is the missing value in the table that represents the rate for marie?

	rate (part/min)	time (min)	part of windows washed
marie	?	\\(t\\)	\\(\frac{1}{60}t\\)

options: \\(60t\\), \\(\frac{1}{60}\\), \\(\frac{1}{60}t\\), \\(60\\)

Explanation:

Step1: Recall rate formula

Rate is defined as the part of work done per unit time. For a task that takes \( T \) minutes to complete alone, the rate \( r \) is \( \frac{1}{T} \) (part per minute), since in \( T \) minutes, 1 whole task is done, so per minute it's \( \frac{1}{T} \) of the task.

Step2: Apply to Marie's rate

Marie takes 60 minutes to wash the windows by herself. Using the rate formula \( r=\frac{1}{T} \), where \( T = 60 \) minutes, her rate should be \( \frac{1}{60} \) part per minute.

Answer:

\(\frac{1}{60}\)