A construction supplier provides two types of steel components: girders and industrial bolts. The mass of each component is normally distributed. A girder has a mean mass of 520 kg and a standard deviation of 8 kg. An industrial bolt has a mean mass of 60 kg and a standard deviation of 3 kg.
One girder and 8 industrial bolts are selected at random. Find the probability that the mass of the girder exceeds the combined mass of the 8 industrial bolts.
A single girder and a single bolt are selected at random. Determine the probability that the mass of the girder is less than 8 times the mass of the single bolt.
616 exam-style questions on Edexcel A Level Maths The Normal Distribution, covering 3.1 The Normal Distribution, 3.2 Finding Probabilities for Normal Distributions, 3.3 The Inverse Normal Distribution Function, 3.4 The Standard Normal Distribution, 3.5 Finding the mean and standard deviation, 3.6 Approximating a Binomial Distribution, and 3.7 Hypothesis Testing with the Normal Distribution. Each one has a worked solution and a mark scheme showing where the marks go.