Correct Answer - Option 1 : 27 days

**Given:**

A is twice as efficient as B and together they can finish a work in 18 days.

**Formula used:**

Men × Day = Total work

**Calculation:**

According to the question,

A = 2B

⇒ A/B = 2/1

⇒ Total work = (2 + 1)× 18

⇒ 54

A alone can finish the work

⇒ 54/2

⇒ 27

**∴ A alone can finish the work in 27 days.**