IMC 2008 Q4
4. What percentage of the large 5 × 5 square is shaded?
- A 40%
- B 60%
- C \(66\frac{2}{3}\)%
- D 75%
- E 80%
Intermediate Mathematical Challenge 2008, Question 4. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: B 60%
The large square is made up of 25 small squares, 15 of which are shaded. So \(\dfrac{15}{25}\) of the large square is shaded, corresponding to \(\tfrac{15}{25}\) × 100% = 60%.
Solution © UK Mathematics Trust, from the IMC 2008 solutions.