IMC 2004 Q16
16. If the pattern shown is continued, what number will appear directly below 400?
- A 438
- B 439
- C 440
- D 441
- E 442
Intermediate Mathematical Challenge 2004, Question 16. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C 440
Note that the number at the end of the \(n\) th row is \(n^2\), so 400 will lie at the end of the 20 th row. The row below will end in 212, i.e. 441, so the number directly below 400 will be 440.
Solution © UK Mathematics Trust, from the IMC 2004 solutions.