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?

A table showing Rate in part per minute, Time in minutes, and Part of Windows Washed. The first row shows Lea, and has StartFraction 1 Over 80 EndFraction, t, and StartFraction 1 Over 80 EndFraction t. The second row shows Marie, question mark, t, and StartFraction 1 Over 60 EndFraction t.

StartFraction 1 Over 60 EndFraction t
60
StartFraction 1 Over 60 EndFraction tt
60t

Answer 1

A. 1/60

Explanation:

I just did the test

Answer 2

Answer: To find the missing value in the table that represents the rate for Marie, we can set up a rate equation based on the information given.

Let's use the formula: Rate × Time = Work

For Lea:

Rate (Lea) = 1/80 (part per minute) [Given]

Time (Lea) = t (minutes) [Given]

For Marie:

Rate (Marie) = ? (part per minute) [To find]

Time (Marie) = t (minutes) [Given]

Both Lea and Marie are working together, so the combined rate will be the sum of their individual rates.

Combined Rate = Rate (Lea) + Rate (Marie)

Now, plug in the values:

Combined Rate = 1/80 + Rate (Marie)

Since they are washing all the windows, the work done by Lea and Marie together is equal to 1 (the whole task).

Combined Rate × Time (Combined) = 1

(1/80 + Rate (Marie)) × t = 1

Now, solve for Rate (Marie):

1/80 + Rate (Marie) = 1/t

Subtract 1/80 from both sides:

Rate (Marie) = 1/t - 1/80

Now, plug in the value of t = 60 (because Marie takes 60 minutes to wash the windows by herself):

Rate (Marie) = 1/60 - 1/80

To make the denominators the same, find a common denominator, which is 240:

Rate (Marie) = 4/240 - 3/240

Rate (Marie) = 1/240

So, the missing value in the table that represents the rate for Marie is 1/240 part per minute.