Let A3BC and DE2F be four-digit numbers where each letter represents a different digit greater than 3. If the sum of the numbers is 15902, then what is the difference between the values of A and D?

Correct Answer: (C) 3

In the addition $A3BC + DE2F = 15902$ with distinct digits $> 3$: from tens, $1 + B + 2 = 10$$\implies$ B = 7 (carry 1); from hundreds, $1 + 3 + E = 9$$\implies$ E = 5. With 5 and 7 used, the remaining digits $\{4, 6, 8, 9\}$ must form $C + F = 12$ and $A + D = 15$. Thus $\{C, F\} = \{4, 8\}$ and $\{A, D\} = \{6, 9\}$. The difference between A and D is $|9 - 6| = 3$.