The correct response is:
No, because y represents the total number of $5 bills. You cannot have a half bill.
The values of x (the number of $1 bills) and y (the number of $5 bills) must be non-negative integers. Since y is given as 22.5 in the point (30, 22.5), this indicates that Alejandro would have a fractional number of $5 bills, which is not possible. Therefore, the point (30, 22.5) is not a viable solution.