The mean of three numbers x, y and z is x.

What is the mean of y and z?

This problem is taken from the UKMT Mathematical Challenges.

You can find more short problems, arranged by curriculum topic, in our short problems collection.

Generalising. Simultaneous equations. Inequalities. Circle properties and circle theorems. Working systematically. Polynomial functions and their roots. Expanding and factorising quadratics. Regular polygons and circles. Creating and manipulating expressions and formulae. Mathematical reasoning & proof.