Jim and Regina can complete one job in 4 hours when working together. When working alone, Jim works twice as quickly as Regina. How long will it take each of them to do the job when working alone?

Answer 1

1/R + 1/J = 1/4

1/R + 1/R/2 = 1/4, multiply by 4R

1/R + 2/R = 1/4

4 + 8 = R

R = 12 hours working alone for Regina

J = 6 hours working alone for Jim

1/12 + 1/6 = 1/4

1/12 + 2/12 = 3/12 = 1/4