Answer: it will take 5 people 6.4 hours to do the work.
Explanation:
The number of hours required to do a job varies inversely as the number of people working. Let h represent the number of hours required to do the job. Let p represent the number of people working. Therefore,
h is inversely proportional to p
Introducing a constant of variation, k, it means that
h = k/p
It takes 8 hours for 4 people to paint the inside of a house. Therefore
8 = k/4
k = 8×4 = 32
The formula becomes
h = 32/p
To determine how many hours it will take 5 people to do the work, we will substitute p = 5 into the formula. It becomes
h = 32/5 = 6.4 hours