6 x 12 men = 8 x 18 women = 18 x 10 children
⇒ 12 men = 24 women = 30 children
⇒ 2 men = 4 women = 5 children
Now, 4 men + 12 women + 20 children = 4 men + 6 men + 8 men = 18 men
Time to do remaining work in 1 man = (6 x 12 - 18 x 2) = 36 days
∴ Required number of men to finish the work in 1 days = 36