Lesson: Divisibility Rules

Comment on Divisibility Rules

please solve brent
greenlight-admin's picture

Hi Brent,

In this practice problem, it says that 126 is divisible by 6, which I can see is true. But 9 is not divisible by 2?? SO that doesn't follow the rule, right? I am guessing the number needs to be a certain number of digits long for these rules to apply.

greenlight-admin's picture

Question link: https://greprepclub.com/forum/on-a-weekend-6-college-friends-went-skiing...

I think you might be confusing a few divisibility rules.
If a number is divisible by 2, then its units digit must be even (0, 2, 4, 6, or 8)
If a number is divisible by 3, then the sum of its digits must be divisible by 3.
If a number is divisible by 6, then it is divisible by 2 AND by 3

126 has an even units digit (6). So, 126 is divisible by 2.
1 + 2 + 6 = 9, and 9 is divisible by 3. So, 126 is divisible by 3.
Since 126 is divisible by 2 AND by 3, we know that 126 is divisible by 6

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