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.
Practise Edexcel A Level Maths Finding the mean and standard deviation with exam-style questions for A Level Maths. 48 questions, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
