Question

If Naomi were to paint her living room alone, it would take 5 hours. Her sister Jackie could do the job in 8 hours. How many hours would it take them working together? Express your answer as a fraction reduced to lowest terms, if needed.

Answer 1

Answer: it would take them 40/13 hours

Step-by-step explanation:

If Naomi were to paint her living room alone, it would take 5 hours. it means that the rate at which she paint her living room alone is 1/5

Her sister Jackie could do the job in 8 hours. it means that the rate at which Jackie paint the living room is 1/8

If they work together, they would work simultaneously and their individual rates are additive. This means that their combined working rate would be

1/5 + 1/8 = (8 + 5)/40 = 13/40

Assuming it takes t hours for both of them to clean the room working together, the working rate per hour would be 1/t. Therefore,

13/40 = 1/t

t = 40/13 hours