Correct Answer - Option 4 : 16 days

**Given:**

A can do a job = 24 days

B's efficiency = 50% more than A

**Concept used:**

The efficiency of work done is always inversely proportional to the time taken to do the work

**Formula used:**

Time is taken = Total work/Efficiency

**Calculations:**

Let the efficiency of A = 100%

Then, the efficiency of B = 100% + 50%

⇒ 150%

The ratio of efficiencies of A and B = 100% ∶ 150%

⇒ 2 ∶ 3

The ratio of number of days taken to complete work by A and B = 3 ∶ 2

Number of days taken to complete by B = (24/3) × 2

⇒ 16 days

**∴ B alone can finish the job in 16 days**