Correct Answer - Option 3 : 67.25 kg

**Given:**

Average weight of 12 boys = 68 kg

Wrong weight of one boy = 54 kg

Actual weight = 45 kg

**Formula used:**

Average = sum of observations/total number of observations

**Calculation:**

Total weight = 12 × 68 = 816 kg

Actual weight = 816 - 54 + 45 = 807

∴ Actual average = 807/12 = 67.25 kg

**∴ The average is 67.25 kg**