For Kevin, it takes 10 hours to repair the roof. However, Sam takes 12 hours to complete the same job. If working together, how long would they take?

5.45 hours or 5 hours 27 minutes to nearest minute.

Step-by-step explanation:

We work in rates per hour.

Kevin does 1/10 of the roof in an hour and Sam does 1/12 of the roof/hour.

Now we add to get the equation:

1/10 + 1/12 = 1 / x    where x is the time they take to repair the roof working together.

Multiplying through by the LCM 60x:

6x + 5x = 60

11x = 60

x =60/11

x = 5.45 hours.

news channels,news papers,and the internet

x/3-10=8

x/3=18

x=48