Explanation:

- The average weight of six persons is 30 kg, so their total weight is 6 * 30 = 180 kg.

- When a new person joins, the total becomes 7 persons with an average of 28 kg, making the new total weight 7 * 28 = 196 kg.

- The weight of the new person can be found by subtracting the original total from the new total: 196 kg - 180 kg = 16 kg.

Option 1: 22 kg

- Incorrect. It does not match the calculated weight of the new person.

Option 2: 14 kg

- Incorrect. It is less than the calculated 16 kg.

Option 3: 15 kg

- Incorrect. It is also less than the correct calculation.

Option 4: 16 kg –

- Correct. Matches our calculation for the new person’s weight.