Khaliq produces and sells toy cars. The material for each car costs him $4. He has been selling them for $8 each and averaging sales of 40 per week. He has been told by Kiarash that he could charge more but has found that for each $0.50 increase in price, he would lose 4 sales each week. How much should Khaliq charge per car in order to have the greatest profit? What is the greatest
profit?