If a supermarket thinks it can raise sales by offering 1 month of free credit. The price per carton is $100, and the cost per item $65.

If a supermarket thinks it can raise sales by offering 1 month of free credit. The price per carton is $100, and the cost per item $65. The unit sales will increase from 1,050 to 1,110 per month if credit is granted. Assume all customers pay their bills and take full advantage of any credit period offered.