A level maths

Hi,

Does anyone know how to answer the AQA A-level maths stats 2021 assessment resources. More specifically the final question.

Elizabeth's bakery makes brownies. It is known that the mass, X grams, of a brownie may be modelled by normal distribution. 10% of the brownies have a mass of less than 30g. 80% of the brownies have a mass that is greater than 32.5g.
a) Find the mean and standard devisation of X. (7)
b)
i) P(X=/35) (1) --doesn't equal 35
ii) P(X<35) (2)
c) Brownies are baked in batches of 13. Calculate the probability that, in a batch of brownies, no more than 3 brownies are less than 35 grams. YOu may assume that the masses of the brownies are independent of each other (2)

sure i did it the other day do you want just the answers or how you get them too?

Hi,

Does anyone know how to answer the AQA A-level maths stats 2021 assessment resources. More specifically the final question.

Elizabeth's bakery makes brownies. It is known that the mass, X grams, of a brownie may be modelled by normal distribution. 10% of the brownies have a mass of less than 30g. 80% of the brownies have a mass that is greater than 32.5g.
a) Find the mean and standard devisation of X. (7)
b)
i) P(X=/35) (1) --doesn't equal 35
ii) P(X<35) (2)
c) Brownies are baked in batches of 13. Calculate the probability that, in a batch of brownies, no more than 3 brownies are less than 35 grams. YOu may assume that the masses of the brownies are independent of each other (2)

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