posted by Joe .
Find the four-digit number described by these three clues.
1) The first digit is one-third of the third digit.
2) The fourth digit is twice the second digit.
3) The first and third digits add up to twice the sum of the second and fourth digits.
The first digit has to be 1,2,or 3, it can't be anything else.
The second digit can be 1,2,3,4
The final clue lets you determine which digits it is.