Question

Sandy and sally were able to paint a a at house in 5 hours together: it takes sally 9 hours to finish this job alone. Without help, how long would it take sandy to finish this job?

I don’t understand how to solve this question. plz help

Answer 1

9/44 of an hour, or just over 12 minutes

Explanation:

Person 1 + Person 2 divided by Person 1 x Person 2 = Both together

9 + x / 9*x = 5

9+x/9x = 5

Multiply both sides by 9x

9 + x = 45x

Subtract x from both sides

9 = 44x

Divide by 44 to get x.

9/44 of an hour