5 men and 6 boys can do a work in 6 days and 4 women and 1 boy can do the same work in 14 days. If 3 men and 5 boys can do the same work in 9 days, than, how many days can 2 men and 3 boys do the same work?
5 men and 6 boys can do a work in 6 days and 4 women and 1 boy can do the same work in 14 days. If 3 men and 5 boys can do the same work in 9 days, than, how many days can 2 men and 3 boys do the same work? Correct Answer 14 days
(5M + 6B) × 6 = (4W + 1B) × 14
⇒ 30M + 36B = 56W + 14B
⇒ 30M + 22B = 56W ----(1)
(4W + 1B) × 14 = (3M + 5B) × 9
⇒ 56W + 14B = 27M + 45B
⇒ 56W = 27M + 31B ----(2)
From (1) and (2)
⇒ 30M + 22B = 27M + 31B
⇒ 3M = 9B
⇒ M = 3B
⇒ M : B = 3 : 1 ----(3)
From(2)
⇒ 56W = 27 × 3B + 31B = 112B
⇒ W = 2B
⇒ W : B = 2 : 1 ----(4)
From (3) and (4)
Respective ratio of efficiency, M : W : B = 3 : 2 : 1
⇒ Total work = (5M + 6B) × 6 = (15 + 6) × 6 = 21 × 6 = 126
∴ Time taken by 2 men and 3 boys = 126/(2 × 3 + 3 × 1) = 126/9 = 14 days
মোঃ আরিফুল ইসলাম
Feb 20, 2025