The mass of a cheese biscuit has a normal distribution with mean 6 g and standard deviation 0.2 g. Determine the probability that

(a) a collection of twenty-five cheese biscuits has a mass of more than 149 g.

(b) a collection of 30 cheese biscuits has a mass of less than 180 g.

(c) twenty-five times the mass of a cheese biscuit is less than 149 g. The mass of a ginger biscuit has a normal distribution with mean 10 g and standard deviation 0.3 g. Determine the probability that a collection of 7 cheese biscuits has a mass greater than a collection of 4 ginger biscuits. (It may be assumed that all the biscuits were sampled at random from their respective populations.) (C)