A piece of work can be done by 6 men and 5 women in 6 days or it can be done by 3 men and 4 women in 10 days.Find in how many days it can be done by 9 men and 15 women ? एक काम को 6 आदमी और 5 औरत 6 दिन में पूरा करते है ,जबकि यही काम 3 आदमी और 4 औरत 10 दिन में पूरा करते है । उसी काम को 9 आदमी और 15 औरतें कितने दिन में पूरा करेगी?

Let 1 man's 1 day work = m, 1 woman's 1 day work = w. From given: 6m + 5w = 1/6 (work per day), and 3m + 4w = 1/10. Solving: Multiply second eq by 2: 6m + 8w = 1/5. Subtract from first: -3w = 1/6 - 1/5 = -1/30, so w = 1/90. Then 6m = 1/6 - 5/90 = 15/90 - 5/90 = 10/90, so m = 1/54. For 9 men + 15 women: daily work = 9/54 + 15/90 = 1/6 + 1/6 = 1/3. Days needed = 1/(1/3) = 3. Answer B is correct.