Assertion (A) : The mean age of nine boys is 28 years. If one new boy joins them, new mean age becomes 29 years. The age of new boy is (29 - 28) × 10 years.

Reason (R) : The age of new boy is 29 × 10 - 28 × 9 years.

1. A is true, R is false.

2. A is false, R is true.

3. Both A and R are true.

4. Both A and R are false.