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.
225 exam-style questions on CCEA A Level Maths 4.5.1 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.