Q. local supermarket buys lettuce each day to ensure really fresh make. Each morning any lettuce which is left from previous day is sold to a dealer which resells it to farmers who use it to feed their animals. This week supermarket can buy fresh lettuce for $4.00 a box. Lettuce is sold for $10.00 a box also dealer which sells old lettuce is willing to pay $1.50 a box. Past history says which tomorrow's demand for lettuce averages 250 boxes with a standard deviation of 34 boxes. Elucidate how many boxes of lettuce should supermarket purchase tomorrow?