Correct Answer - Option 1 : 12 days

**Given:**

4 women and 3 men can complete a task in 12 days

A woman is thrice efficient as a man → W / M = 3 / 1

**Formula used:**

M_{1} × Eff_{1} × D_{1} = M_{2} × Eff_{2 }× D_{2}, where M = number of workers, D = number of days and Eff. = efficiency of worker

**Calculation:**

Let ‘D’ be the time taken by 15 men to complete the same task.

(4 × 3 + 3 × 1) × 12 = (15 × 1) × D

⇒ D = 180/15 = 12 days = time taken by 15 men to complete the same task.