Question

It takes Doug 6 days to reroof a house. If Doug's son helps him, the job can be completed in 4 days. How long would it take Doug's son, working alone, to do the job?

Answer 1

`4( (1)/(6)+ (1)/(x))=1`

`(1)/(6) + (1)/(x) = (1)/(4)`

`(1)/(x) = (1)/(12)`
x=12

Answer 2

rate of doug is 1 roof in 6 days.
which means he could do 2/3 of a roof in 4 days, whixh means his son does 1/3 of a roof in 4 days, whhich is 1 roof per 12 days.