Question

Max and Maggie have to clean the house. It takes Max 12 hours to clean the house, while Maggie can complete the task in 4 hours. Their sister says that it will take 3 hours to complete if they work together. Explain each step in solving this equation, and determine if the sister is correct or not.

Answer 1

The older sister is correct.
1/12+1/4=1/x, with the numerators being the amount and the denominators being the time. We'll multiply them all by the GCF
x+3x=12
Then all we need to do is solve for x:
4x=12
x=3