Let us suppose that 8 men require x days to tar the road.

Number of days required by 10 men to tar the road = 4

The number of men and the number of days required to tar the road are in inverse proportion.

∴ 8 × x = 10 x 4

∴ x = (10 x 4)/8

∴ x = 5

∴ 8 men will require 5 days to tar the road.