Answer to Question #83464 in Statistics and Probability for Liza

Question

Packets of milk powder produced by a machine were found to have a normal distribution with a mean mass of 650g and a standard deviation of 10g.
(a) Find the probability that a packet selected at random will have a mass between 620g and 655g.
(b) If 500 packets are selected at random, how many of them will have a mass of more than 660g?
(c) It is found that 10% packets of milk powder will have a mass of less than k grams. Calculate k.