Cam had 8000 $.90 has been on groceries after buying 10 grapefruits she had $3.90 left each grapefruit cost same amount. What is the price of one grapefruit

Cam spent 8000 - 3.9 = $796.1 on 10 grapefruits.

Each grapefruit cost 796.1 / 10 = $79.61.
Therefore, the price of one grapefruit is $79.61.