a set of pencils sells for 1.75 and costs 0.40 to make
if 500 sets are sold...
500(1.75) = 875...this is revenue
500(0.40) = 200....this is expenses
profit = revenue - expenses
profit = 875 - 200
profit = 675
20% of the profit goes to the school...
0.20(675) = $ 135 <=== this is what goes to the school