Max purchased a box of green tea mints. the nutrition label on the box stated that a serving of three mints contains a total of 10 calories

Full box=180 calories
C(x)=number of calories
x=number of mints

therefor
full box=180=(10/3)x
180=(10/3)x
solve for x aka number of mints per box

multiply both sides by 3/10 ( since 10/3 times 3/10=30/30=1 so 1x)

540/10=x
54=x

54 mints per box

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.