Answer:

It will take 1 day and 21 hours for 8 men to finish the house.

The Proportion used is Inverse Proportion

Step-by-step explanation:

y = k/x --- days spent = (constant k)/(number of men)

Find k:

3 = k/5 --- multiply both sides by the y value(5)

15 = k

Lets Find :

y = k/x --- supply our constant k(15)

y = 15/8

y = or  

if you find this answer helpful, marking this answer as brainiest is appreciated.