Answer:
3 hours
Step-by-step explanation:
Xavier can paint the average house in 4 hours
This means that in 1 hour, Xavier paints 1/4 of the house
Mohamad can do it in 12 hours
That means in 1 hour, Mohamad paints 1/12 of the house
Hence,
Together the amount of the house they can paint in 1 hour is
1/4 + 1/12
The Least common denominator is 12
(3 × 1 + 1 × 1)/1#
= 3 + 1/12
= 4/12
= 1/3
Together they can paint 1/3 of the house
The number of hours, that it would take to paint a house if they both worked together is
= 1/3 = 1
Cross Multiply
= 3 × 1
= 3 hours