12 men alone can complete a piece of work in 6 days. Where as 10 men and 21 women together take 3 days to complete the same piece of work. In how many days can 12 women alone complete the piece of work? 12 आदमी एक काम को अकेले 6 दिनों में कर सकते हैं जबकि 10 आदमी और 21 औरतें मिलकर इस काम को 3 दिनों में कर सकते हैं। कितने दिनों में 12 औरतें अकेले इस काम को कर सकती है?

12 men complete work in 6 days, so 12×6 = 72 man-days are needed. 10 men + 21 women take 3 days: (10 men + 21 women) × 3 = 72 man-days equivalent. Let 1 woman's work = w. Then 10 men = 72/3 = 24 man-days per 3 days, so 10 men contribute 10×(man's work)×3. Men's rate = 72/12 = 6 work units/day, so each man = 0.5 units/day. Total work in 3 days by 10M+21W: 10×0.5×3 + 21w×3 = 72. Solving gives w = 1/3. Then 12 women's time: 12×(1/3)×t = 72, so t = 9 days.