She'll pay 20$. If the meat is 6$ for every three pounds and she is trying to buy ten pounds, she's going to be purchasing at least nine pounds of the meat. 3x3=9, so 6x3=18. After that she'd still have a pound to pay for. In this case we divide. 3/3=1, so 6/3=2. One pound of meat is equal to 2$. Add 18$ and 2$ and you get 20$