IMC 2005 Q15
15. To make porridge, Goldilocks mixes together 3 bags of oats with 1 bag containing 20% wheat bran and 80% oats. All the bags have the same volume. What percentage of the volume of Goldilocks' porridge mixture is wheat bran?
- A 5%
- B \(6\frac{2}{3}\)%
- C 20%
- D \(26\frac{2}{3}\)%
- E 60%
Intermediate Mathematical Challenge 2005, Question 15. © UK Mathematics Trust. Original paper on ukmt.org.uk
Answer: A 5%
Four bags of porridge contain one-fifth of a bag of wheatbran. So the proportion of wheatbran in the porridge is 1/20, that is 5%.
Solution © UK Mathematics Trust, from the IMC 2005 solutions.