I don't understand! Someone help please!

Question

Sally can paint a room in 7 hours and John can paint the same room in 10 hours. How long should it take Sally and John to paint the room together?

Answer 1

Hi M., work is based on one hour. Here is the equation to solve:

1/7 + 1/10 = 1/x

Where 1/7 is the work Sally can do in one hour and 1/10 is the work John can do in one hour. 1/x represents the work both can do in one hour.

Now solve for x and you have the answer.

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