Final answer:
The question does not provide enough information to determine the value of 'A' when 'r' is 3 definitively. However, there is a clue suggesting that 'A' could possibly be 15, although this cannot be confirmed without the specific formula relating 'A' to 'r'.
Step-by-step explanation:
The question asks for the value of 'A' when 'r' is 3. From the provided information, it appears that there are equations relating 'A' to 'r', but the specific equation using 'r' is not given. However, a clue is given in one section that describes 'A=14+1=15', suggesting that the value of 'A' might be 15 when there are increments involved. Without the exact relationship between 'A' and 'r', it is impossible to provide a definitive answer. To determine the exact value of 'A' when 'r' is 3, we would need the specific formula that relates these two variables.