Question

Libby can finish a paper in 2 hours. Ethan can finish the same paper in 4 hours. How

long will it take them to finish a paper if they work together?

Answer 1

1.33333 hours

Explanation:

Given :

Time taken by Libby = 2 hours

Time taken by Ethan = 4 hours

rate = 1 / time taken

Libby's rate = 1 /2

Ethan's rate = 1/4

Combined rate = Libby's rate + Ethan's rate

Combined rate = 1/2 + 1/4 = 3/4

Time taken = 1 / combined rate

Time taken = 1 / (3/4)

Time taken = 4 /3

Time taken = 1.33333 hours