John can build a fence in two days; Bill can build the same fence in five days. If john and Bill worked together, how long would it take them to build the fence?

- - John takes 2 days to build a fence. He builds 1/2 of a fence each day.

- - Bill takes 5 days to build a fence. He builds 1/5 of a fence each day.

- - Working together, they build (1/2 + 1/5) of a fence each day.

Before we can add (1/2 + 1/5), we need a common denominator.

The least common multiple of 2 and 5 is 10.

1/2 = 5/10

1/5 = 2/10

(1/2 + 1/5) = (5/10 + 2/10) = 7/10 fence <==

Working together, they build at the rate of 7/10 fence per day.

==> Or 10/7 day per fence.

10/7 day = 1-3/7 day

If their work day is 8 hours, then 1-3/7 day is ...

1 day 3 hours 25 minutes 42.9 seconds of work per fence.

it would take them both three days together to build the fence because it them different amount of days to build the same fence because it said, it took john 2 days to build a fence and it took bill 5 days to build the same fence so subtract 5-2=3 and that's how I got the answer to the question