Digit 2 is smaller than Digit 4Digit 4 is two thirds of Digit 1Digit 1 is two thirds of Digit 3Digit 3 is three times Digit 2
By (3), Digit 3 is divisible by 3:
Digit 3 = 3, 6, 9
By (3), Digit 1 is two thirds of Digit 3:
Digit 1 = 2, 4, 6.
But, by (2), Digit 1 is divisible by 3:
Digit 1 = 6, and Digit 3 = 9.
By (4), Digit 3 is three times Digit 2:
Digit 2 = 3.
By (2), Digit 4 is two thirds of Digit 1:
Digit 4 = 4.
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Puzzle 3
We have been quite lucky with the weather recently, it has got steadily warmer each day, over the last five days.
By this, I mean that the temperature rose by the same amount each day.
The average temperature was 2 °C, and I know it froze on two occasions (0 °C).
I also know the product of the temperatures was over 500 but below 2,000 and each temperature was an integer.
Hint
What must the middle temperature be? Remember that the temperature are in degrees Celsius.
Answer
The temperatures were -6, -2, 2, 6, 10 °C.
Each day increased by a steady 4 degrees.
Reasoning
As the temperature rose steadily each day, we know that the middle temperature (Day 3) was 2 degrees (because the average was 2 degrees).
Since Day 3 was 2 degrees, and there were two negative temperatures, we know that the daily increase must have been at least 3 degrees (otherwise Day 2 would not have been negative).
If we check a daily increase of 3 degrees, the sequence would be -4, -1, 2, 5, 8, but this doesn't work as the product is less than 500.
If we check a daily increase of 4 degrees, the sequence would be -6, -2, 2, 6, 10, which does matches all of the requirements.
If we check a daily increase of 5 degrees, the sequence would be -8, -3, 2, 7, 12, but this doesn't work as the product is more than 2000.
Any larger increase makes the product even larger, so we can stop checking.
So the only possible answer is -6, -2, 2, 6, 10.
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Puzzle 4
I recently travelled from my home town to a distant music concert, on a pedal tricycle, of all things! My wonderful, three-wheeled tricycle.
I knew that the epic 2,345 mile trip would wreak havoc on the tyres, but luckily I took along 4 spares!
Instead of waiting for any single tyre to fail, I decided that I would rotate the tyres evenly, making sure that by the end of the trip, all seven tyres had travelled exactly the same distance.
