The times it takes students to complete a test are normally distributed with a mean of 58 minutes and a standard deviation of 12 minutes.
Find the time by which 90% of students complete the test.
284 exam-style questions on CCEA A Level Maths 4.5 Statistical distributions (A-level only), covering 4.5.1 Statistical distributions (A-level only) and 4.5.2 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.