September 2015 Logic & Maths Problems – Solutions

1. Yellow opposite orange, red opposite green, pink opposite blue

2. A. Emily B. Colin C. Fred D. Irene

3. The hole will become larger.

4. Treble 13, Double 18, single 16

5. 3

6. The water level of the pool will fall (The cannonball is much denser than the water. Let the cannonball have a volume of x litre. Assume the cannonball is ten times as dense as the water. Its mass will therefore be 10x kg. When the cannonball is placed in the boat, the boat settles by an amount which displaces 10 kg of water or 10x litres of water. However, when the cannonball is taken out of the boat and placed directly in the water, it only displaces its own VOLUME of water or x litres. This will have the same effect on the water level of the pool as taking 9x litres out.)

7. There are no “E”s

8. Treble 18, double 4, single 13

9. 2519 prisoners

10. The rule is: double the first number then take away 8. The answer is therefore 20