Help With The Two Following Questions ! PLEASE ❤️

Kayla and alberto are selling fruit for a school fundraiser. customers can buy small boxes of grapefruit and large boxes of grapefruit. kayla sold 3 small boxes of grapefruit and 1 large box of grapefruit for a total of $65. alberto sold 1 small box of grapefruit and 1 large box of grapefruit for a total of $55. what is the cost each of one small box of grapefruit and one large box of grapefruit?

What is always true when two whole numbers are subtracted?

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64