The time, T T\,T minutes, taken for a student to complete a logic puzzle follows a normal distribution. Data shows that 25% of students complete the puzzle in less than 25 minutes, while 15% take more than 45 minutes.
Find the mean and standard deviation of the time taken to complete the puzzle.
328 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.