IMC 2016 Q9
9. The world's fastest tortoise is acknowledged to be a leopard tortoise from County Durham called Bertie. In July 2014, Bertie sprinted along a 5.5 m long track in an astonishing 19.6 seconds.
What was Bertie's approximate average speed in km per hour?
- A 0.1
- B 0.5
- C 1
- D 5
- E 10
Intermediate Mathematical Challenge 2016, Question 9. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: C 1
Bertie travelled 5.5 m in 19.6 s, which is just less than one-third of a minute. So his average speed was approximately 16.5 m per minute, which is equal to 990 m in one hour, as 16.5 × 60 = 990. Now 990 m = 0.99 km, so Bertie's approximate average speed was 1 km per hour.
Solution © UK Mathematics Trust, from the IMC 2016 solutions. Longer versions with investigations: Solutions and investigations (PDF).