You order from a catalog the following office supplies: 10 boxes of paper, each box is 6 pounds and 36 boxes of pens, each box weighs 12 ounces. shipping charges are $12.00 for the first 20 pounds, $10.00 for the next 30 pounds, $0.50 per pound for the next 50 pounds. what will the shipping charges be?

$40.50 10 boxes at 6lbs = 60lbs

             36 boxes at 12 ounces = 432 ounces dived by 16(16 oz in a lbs)= 27 lbs

             60 lbs plus 27 lbs = 87 lbs total weight

 87lbs - 20lbs($12)= 67lbs - 30 lbs($10)= 37lbs x .50($.50 per pound)= $18.50

$12+$10+$18.50= $40.50

answer: c

because if you look at the chart you can see a pattern and compare it to the question he simplify out your

but i think the formula is f(x)=6x