PK 2015 Q9
9. In the grid, each small square has side of length 1. What is the minimum distance from ‘Start’ to ‘Finish’ travelling only on edges or diagonals of the squares?
- A \(2\sqrt{2}\)
- B \(\sqrt{10} + \sqrt{2}\)
- C \(2 + 2\sqrt{2}\)
- D \(4\sqrt{2}\)
- E 6
Pink Kangaroo 2015, Question 9. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C \(2 + 2\sqrt{2}\)
The shortest routes consist of two diagonals (right and down) each of length \(\sqrt{2}\), and two sides of length 1, giving a total length \(2 + 2\sqrt{2}\).
Solution © UK Mathematics Trust, from the PK 2015 solutions.