Answer: it takes themApproximately 2.7 hours to paint the house together
Explanation:
Sam can paint a house in 8 hours. This means that sam's unit rate of working is 1/8
Joe can paint the same house in 4 hours.
This means that Joe's unit rate of working is 1/4
If they work together, it would take them lesser time because they are working simultaneously. This means that their unit rates are additive. Combining their unit rates, it becomes
1/8 + 1/4 = 3/8
Assuming that if they work together, it will take them t hours. Therefore, Their unit rate of working will be 1/t.
Therefore,
3/8 = 1/t
3t = 8
t = 8/3 = 2.667
Approximately 2.7 hours