Correct Answer - Option 4 : 48

**Given:**

Average weight of some persons = 72 kg

Average weight of 5 persons = 66.6 kg

Average weight of 13 persons = 75 kg

**Formula used:**

Average Weight = Total weight/No of persons

⇒ Total weight = Average weight × No of persons

**Calculation:**

Let the initial number of persons be = y

New total weight;

y × 72 + 5 × 66.6 - 13 × 75 = (y + 5 - 13) × (72 - 1.65)

⇒ 72y + 333 - 975 = (y - 8) × 70.35

⇒ 72y - 642 = 70.35y - 562.8

⇒ 72y - 70.35y = 642 - 562.8

⇒ 1.65y = 79.2

⇒ y = 79.2/1.65

⇒ y = 48

**∴ The inital number of persons = 48**