In order to boost sales, a producer of Easter eggs includes a plastic novelty in a randomly choosen 20 % of the eggs. A mother buys an Easter egg for each of her 5 children.

(a) Calculate the probability that at least 2 of the children have novelties in their eggs.

When an egg contains a novelty, the novelty is equally likely to be any of 6 different types.

(b) Calculate the probability that just two of the five children have novelties, and that these novelties are different.

Continues below in reply section

Question

In order to boost sales, a producer of Easter eggs includes a plastic novelty in a randomly choosen 20 % of the eggs. A mother buys an Easter egg for each of her 5 children.

(a) Calculate the probability that at least 2 of the children have novelties in their eggs.

When an egg contains a novelty, the novelty is equally likely to be any of 6 different types.

(b) Calculate the probability that just two of the five children have novelties, and that these novelties are different.

Continues below in reply section

anonymous · Answer

The Question continues here:

Eggs with novelty has a mass which is normally distributed with mean 106.5 g and standard deviation 0.7 g. The others have mass normally distributed with mean 106.0 g and standard deviation 0.1 g

(c) Calculate the probability that an egg chosen at random from those containing a novelty are heavier than one chosen at random from the others

(d) Calculate the probability that two of the eggs chosen at random, the heavier ones contain a novelty. 


(a) (b) and (c) are worth 3 marks
(d) = 6 marks

I've understood (a) (b) and (c) ! It's for (d) i have a problem :/ Please help !