The mass of newborn kittens in a specific breed is normally distributed.
20% of the kittens have a mass of less than 85 grams. 12% of the kittens have a mass of more than 115 grams.
Find the mean and standard deviation of the masses.
147 exam-style questions on OCR A Level Maths 2.4.6 Probabilities using the normal distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.