Question

One maid can clean the house in 2 hours. Another maid can do the job in 8 hours. How long will it take them to do the job working together?
A 16/6 hr
B 8/5 hr
C 1/10 hr
D 1/16 hr

Answer 1

Answer: B 8/5 hr

Step-by-step explanation:

One maid can clean the house in 2 hours. This means that the rate at which she cleans the house per hour is 1/2

Another maid can do the job in 8 hours. This means that the rate at which the other maid cleans the house per hour 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

1/2 + 1/8 = 5/8

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,

5/8 = 1/t

t = 8/5 hour

Answer 2

Answer:

Option B, 8/5 hr

Step-by-step explanation:

1/2 + 1/8

1*4 / 2*4 + 1/8

4/8 + 1/8

5/8 = 1/t

5t / 5 = 8 / 5

t = 8/5

Answer:  Option B, 8/5 hr