If the number 52,1n9, where n represents the tens digit, is a multiple of 3, then the value
of n could be which of the following?
A. 6
B. 5
C. 3
D. 1
E. 0
ps question
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Quick trick for deciding if a number is a multiple of 3:
if the sum of the digits of the number is a multiple of 3, then the whole number is a multiple of 3.
Here we have:
52,1n9 and know that the number is a multipe of 3.
Therefore, 5+2+1+n+9 = a multiple of 3
17 + n = a multiple of 3.
Looking at the choices, only
(d) 1
will give us what we want (since 17+1=18, which is a multipe of 3).
if the sum of the digits of the number is a multiple of 3, then the whole number is a multiple of 3.
Here we have:
52,1n9 and know that the number is a multipe of 3.
Therefore, 5+2+1+n+9 = a multiple of 3
17 + n = a multiple of 3.
Looking at the choices, only
(d) 1
will give us what we want (since 17+1=18, which is a multipe of 3).
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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Here is a great link for divisibility rules:
https://www.mathwarehouse.com/arithmetic ... -tests.php
It has 2,3,4,5,6,7,8,10, and 11
https://www.mathwarehouse.com/arithmetic ... -tests.php
It has 2,3,4,5,6,7,8,10, and 11
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