Question

Shawn and Ellie are construction workers. Shawn can complete a concrete job in 4 hours, while Ellie can complete it in 6 hours. The foreman says that it will take them 5 hours to complete it if they work together. Explain each step in solving this equation, and determine if the foreman is correct or not.

Answer 1

For the answer to the question above, I'll explain my answer below.
Shawn ALONE = 4 hours

Shawn ALONE in 1 hour = 1/4 of the job

Ellie ALONE in 1 hour = 1/6 of the job

TOGETHER in 1 hour = 1/4 +1/6 = 5/12 of the job

THEY will COMPLETE the job in 12/5 hours

ANSWER 2.4 hours OR 2 hours 24 minutes