Puzzle Details

What four digit number has...

...digit 2 smaller than digit 4 which is two thirds of digit 1 which is two thirds of digit 3 which is three times digit 2?

Working backwards:

Digit3 can only be 3, 6 or 9 (as it's 3 x Digit2).

Digit2 can only be 1, 2 or 3.

Digit1 can only be 2, 4 or 6.

But, since Digit4 is two thirds of Digit1, Digit1 must be 6. Making Digit4 4 and making Digit3 9. Making Digit2 3.

Giving 6394.

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