The local supermarket buys lettuce each day to ensure fresh produce. Each morning any lettuce that is left from the previous day is sold to a dealer that it resells to farmers who use it to feed their animals. This week the supermarket can buy fresh lettuce for $5.00 a box. The lettuce is sold for $10.00 a box and the dealer that sells old lettuce is willing to pay $3.50 a box. Past data shows that daily demand for lettuce is normally distributed with mean 250 boxes and standard deviation of 34 boxes. How many boxes of lettuce should supermarket purchase tomorrow if past data is unreliable and the supermarket manager estimates the daily demand to be uniformly distributed from 300 boxes to 400 boxes?