Using the concept of man-days, product of men/women and days is constant (work is constant) ⇒ 24 men × 15 days = 36 women × 22 days ⇒ 24 × 15 = 36 × 22 ⇒ 10 men = 22 women ---- (1) Amount of work done by 20 women and 10 men together working for (33/7) days ⇒ 20 women + 10 men ⇒ 20 women + 22 women ⇒ 42 women Amount of work done in 33/7 days by women, (36 × 22) /1 = (42 × 33/7) /Work Done Work done = (42 × 33) / (7 × 36 × 22) ⇒ Work Done = (1/4) Remaining amount of work = 1 – (1/4) = 3/4 Number of days taken for which 10 men initially to complete (3/4) of the work ⇒ (24 × 15) /1 = (10 × No of Days) / (3/4) Number of days = 24 × (15/10) × (3/4) = 27 days ∴ Number of days for which 10 men worked initially = 27 days