Pam currently owns 180 shares of XYZ, which is about to pay a $1.64 per share dividend, and has a cumulative dividend price of $27. Pam would prefer a $2.72 per share dividend. How many shares of XYZ should she buy or sell, assuming she is selling her shares before the cumulative dividend date?. Please report buying shares as a positive number, and selling shares as a negative number, and give your answer to the nearest tenth of a share.

The answer is -7.2 but I don't know how to get there