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?

10 boxes of paper at 6 lbs each = (10 * 6) = 60 lbs
36 boxes of pens at 12 oz each = (36 * 12) = 432 oz.
there are 16 oz in 1 lbso 432 oz = (432/16) = 27 lbs.
so we have a total weight of (60 + 27) = 87 lbs

shipping charges : $ 12 for first 20 lbs, $ 10 for the next 30 lbsso thats 50 lbs...leaving 37 lbs at 0.50 per lb = 37(0.50) = $ 18.50

for a total of : 12 + 10 + 18.50 = $ 40.50 <==