What is the answer to 3c-7c+a+b

Hannah paid $3.20 for 16 ounces of potato chips. hank paid $3.23 for 17 ounces of potato chips. who paid less per ounces?

Liz is shipping a package to her friend. the maximum weight of a medium flat-rate box is 20 pounds, including the box which weighs 6 ounces. write and solve an inequality to describe the possible weight in pounds, w, of the contents that liz will ship to her friend if she must use a medium flat-rate box. use the drop-down menus to explain your answer.

3/4 = c/36 i need with this fraction proble.