The Integer N will be divisible by 36 if it is divisible by the Prime Bases that make up 36’s Prime Factorization.
36 = (2)^2 * (3)^2
Divisibility Rule for (2)^n power
If the last n digits are divisible by (2)^n
Then the number will be divisible by (2)^n
As given, the last 2 digits of n are 96, which is divisible by 4
Thus all we need to know is whether the number n is divisible by 9
Question: do the Digits of N sum to a Multiple of 9?
Or
Is: a + b + c + d + 15 = Multiple of 9?
S1: (a + b + c + d) = 9k + 3
Where k = non negative integer
Inserting this result into the question stem:
(9k + 3) + 15 = 9k + 18
Rule: when you add 2 multiples of some Number X —— the result will be another multiple of X
9k + 18 = Multiple of 9
Which means the digits of n must sum to a Multiple of 9, meaning n will be divisible by 9 and thus 36. YES
S1 is sufficient alone
S2: the digits (a+ b + c + d) sum to a multiple of 3
Case 1: they could sum to 6, in which case the sum of the digits of N = 21 and N would NOT be divisible by 9
Case 2: the digits could sum to 12, a multiple of 3, in which case the sum of the digits of N = 27 and N would be divisible by 9
Since we get conflicting answers of yes and no, s2 is not sufficient.
A: S1 alone is sufficient
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