Items produced by a manufacturing process are supposed to weigh 90 grams. The manufacturing process is such, however, that there is variability in the items produced and they do not all weigh 90 grams. The distribution of weights can be approximated by a Normal distribution with mean 90 grams and a standard deviation of 2 grams.

a.) what percentage of the items will weigh less than 87 grams?

b)How heavy must an item weigh in order to be heavier than 90% of all items produced?