Correct Answer - Option 1 : 16 days

**Given: **

Devika completed the school project in = 20 days

Aarav is 25% more efficient than Devika.

**Calculation:**

Let the days taken by Aarav to complete the work be x

The ratio of time taken by Aarav and Devika = 125 : 100

⇒ 5 : 4

∴ 5 : 4 :: 20 : x

⇒ x = (4 × 20)/5

⇒ x = 16

**∴ Aarav takes 16 days. **