Question

It takes Alice 90 minutes to put a futon frame together, and it takes Maya 60 minutes to put the same

type of frame together. If they worked together, how long would it take to put a frame together?

Answer 1

36 minutes

Explanation:

The equation to determine the time together is

1/a + 1/b = 1/c where a and b are the times alone and c is the time together

1/90 + 1/ 60 = 1/c

Multiply each side by 180c to clear the fractions

180c( 1/90 + 1/ 60 = 1/c)

2c + 3c = 180

5c = 180

Divide each side by 5

5c/5 = 180/5

c =36