100 people are invited to a party. Each guest is estimated to eat 0 or 1 or 2 sandwiches with probabilities, .3, respectively.

1.      100 people are invited to a party. Each guest is estimated to eat 0 or 1 or 2 sandwiches with probabilities, .2, .5, .3, respectively. How many sandwiches should be ordered to be 90% confidence interval for enough sandwiches for every one? Use central limit theorem.