Correct Answer - Option 2 : 1 ∶ 2
Given:
6 men and 5 women can complete a piece of work in 6 days while 12 men and 6 women can complete the same piece of work in 4 days.
Concepts used:
Time = Work/Efficiency
Calculation:
Let work efficiency of 1 man be M and work efficiency of 1 woman be W.
Work = Efficiency × Time
⇒ Total work by 6 men and 5 women = (6M + 5W) × 6 = 36M + 30W
⇒ Total work by 12 men and 6 women = (12M + 6W) × 4 = 48M + 24W
As total work remains same,
⇒ 36M + 30W = 48M + 24W
⇒ 48M – 36M = 30W – 24W
⇒ 12M = 6W
⇒ M/W = ½
∴ Ratio of work efficiency of 1 man and 1 woman is 1 ∶ 2.