Answer:
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.
