Final answer:
The subject of this question is Mathematics. The solution involves finding the total number of ringtones by using the algebraic expression '2x + 3'.
Step-by-step explanation:
The subject of this question is Mathematics. The question is asking about the number of ringtones that Mary has in comparison to another quantity. In this case, the quantity is described as 'twice as many' as Mary's number of ringtones, and then '3 more' than that quantity. To solve this problem, we can use algebraic expressions:
- Let's assume the number of ringtones Mary has is 'x'.
- If another person has twice as many ringtones as Mary, then that person has '2x' ringtones.
- Adding 3 to the previously calculated quantity, we get '2x + 3' ringtones in total.
Therefore, the subject of this question is Mathematics, and the solution to find the total number of ringtones is '2x + 3'.