If 8 men or 12 women can complete a work in 40 days, how many days would it take 20 men and 18 women to complete twice the work?

Question: If 8 men or 12 women can complete a work in 40 days, how many days would it take 20 men and 18 women to complete twice the work?

Solution:
Here,
8 men = 12 women
∴ 1 man = 12/8 = 3/2 women
∴ 20 men = 20 × 3/2 = 30 women

∴ 20 men and 18 women together = 30 + 18 = 48 women

12 women can complete the work in 40 days
∴ 1 woman can complete the work in 40 × 12 = 480 days
∴ 48 women can complete the work in 480/48 = 10 days

Hence, to do twice the work, the time needed = 10 × 2 = 20 days