You’ve been falling behind in your maths coursework and have dipped into ‘cause for concern’ for you abilities. Dr Ratio is your uni maths tutor, over the hour he’s become gradually more irritated at your inability.

“Come on now, this one is easy. If x is the mean average of m and 9, y is the average of 2m and 15, and z is the average of 2m and 18, what is the average of x, y and z in terms of m?”

he looks at you with a hopeful smile, which is very distracting due to his attractiveness