Given: 2 men and 3 women working 7 hours a day finish a piece of work in 5 days 4 men and 4 women working 3 hours a day do the same work in 7 days Formula used: Total work = Efficiency × Time taken Calculation: let M and W be men and women respectively (2M + 3W) × 7 hours × 5 days = Total work --------(1) (4M + 4W) × 3 hours × 7 days = Total work --------(2) (1) = (2) (2M + 3W) × 5 = (4M + 4W) × 3 hours 10M + 15W = 12M + 12W 3W= 2M Ratio of Men to Women M:W = 3:2 Substitute the ratio in equation(1) ( 6 + 6 ) × 7 hours × 5 days = Total work 12 × 7 × 5 = 420 Total Work = 420 Work done by 7 men working 4 hours a day let X be the number of days 420 = 7 × 3 × 4 hours × X X = 5 Number of days is 5 Answer is 5