Let Anna bought x number of wrapped strings and y number of unwrapped strings.
Anna purchased 32 strings. Therefore,
x+y=32 (i)
Again, Wrapped strings cost $4.49 each and unwrapped strings cost $2.99 each and she paid total $107.68
Therefore,
4.49x+2.99y=107.68 (ii)
Now, let us solve the system of linear equations (i) and (ii).
The two lines intersect each other at the point (8,24).
Therefore, the solution is
x=8
y=24
Hence, Anna bought 8 wrapped strings and 24 unwrapped strings