Find the different one:

Looking at the four numbers, I need to identify what makes one different from the others.

Let me check the sum of digits for each number:

For 3085: $3 + 0 + 8 + 5 = 16$

For 9900: $9 + 9 + 0 + 0 = 18$

For 5116: $5 + 1 + 1 + 6 = 13$

For 8179: $8 + 1 + 7 + 9 = 25$

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A number is divisible by 9 if and only if the sum of its digits is divisible by 9.

Checking each sum:

• 16 is not divisible by 9
• 18 is divisible by 9
• 13 is not divisible by 9
• 25 is not divisible by 9

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9900 is the only number divisible by 9.

Therefore, the different one is Option 2.