IMC 2007 Q8
8. The mean of three numbers \(x\), \(y\) and \(z\) is \(x\). What is the mean of \(y\) and \(z\) ?
- A \(\tfrac{1}{2}x\)
- B \(x\)
- C \(2x\)
- D \(3x\)
- E \(4x\)
Intermediate Mathematical Challenge 2007, Question 8. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: B \(x\)
The sum of the three numbers is \(3x\), so \(y + z = 2x\). Hence the mean of \(y\) and \(z\) is \(x\).
Solution © UK Mathematics Trust, from the IMC 2007 solutions.