Question

Jeff can put shingles on a house in 9 hours while David can shingle the same house in 6 hours. If the two work together, how long would it take them to shingle the house?

about 4 hours and 30 minutes
about 4 hours
about 3 hours and 30 minutes
about 3 hours

Answer 1

3 hours and 30 minutes

Step-by-step explanation:

W =
`(1)/(9)t + (1)/(6)t\\\\`

1 =
`(2)/(18)t + (3)/(18)t`

1 =
`(5)/(18)t`

`(18)/(5) = t`

3.6 → 60 decimal hours equals 36 minutes so the answer would be 3 hours and 30 minutes.

The chart I have attached shows decimal hours converted to hours. It helped me with this question.

Answer 2

3 hours and 30 minutes

Step-by-step explanation: