IMC 2007 Q2
2. The information display on a train shows letters by illuminating dots in a rectangular 5 × 8 array. In the letter ‘t’ shown, what fraction of the dots in the array is illuminated?
- A \(\dfrac{9}{20}\)
- B \(\dfrac{19}{40}\)
- C \(\dfrac{1}{2}\)
- D \(\dfrac{21}{40}\)
- E \(\dfrac{11}{20}\)
Intermediate Mathematical Challenge 2007, Question 2. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C \(\dfrac{1}{2}\)
There are forty dots in the 5 × 8 array and twenty of these are illuminated to form the letter ‘t’.
Solution © UK Mathematics Trust, from the IMC 2007 solutions.