GK 2019 Q3
3. Kerry writes a list of all the integers from 1 to \(n\) on a whiteboard. She uses the digit 0 five times and the digit 9 six times. What is the value of \(n\)?
- A 39
- B 49
- C 59
- D 69
- E 99
Grey Kangaroo 2019, Question 3. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C 59
Kerry uses the digit 0 five times and hence the value of \(n\) is smaller than 60. She uses the digit 9 six times and hence the value of \(n\) is at least 59. Therefore the value of \(n\) is 59.
Solution © UK Mathematics Trust, from the GK 2019 solutions.