GK 2020 Q11
11. Sacha’s garden has the shape shown. All the sides are either parallel or perpendicular to each other. Some of the dimensions are shown in the diagram. What is the length of the perimeter of Sacha’s garden?
- A 22
- B 23
- C 24
- D 25
- E 26
Grey Kangaroo 2020, Question 11. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C 24
Divide the garden up and let the lengths of the various sides be as shown on the diagram. Since all sides are either parallel or perpendicular, \(a + b + c = 3\). Therefore the perimeter of Sacha’s garden is \(3 + 5 + a + x + b + 4 + c + (4 + (5 - x)) = 21 + a + b + c = 24\).
Solution © UK Mathematics Trust, from the GK 2020 solutions.