The time taken to assemble a specific furniture kit is normally distributed with a mean of 140 minutes140\text{ minutes}140 minutes and a standard deviation of 25 minutes25\text{ minutes}25 minutes.
Find the time by which 95% of customers complete the assembly.
228 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.