BTGmoderatorDC wrote:If x is the greatest common factor of 36 and 96, what is the sum of the digits of x?
A. 2
B. 3
C. 4
D. 6
E. 9
OA B
Source: Veritas Prep
Mitch's solution is the approach I'd take, but another way to answer this question is to simply LIST the factors of each value and then find the GREATEST factor they have in common.
When listing factors, it's best to do so
in pairs of values with a given product (either 36 or 96). Here's what I mean:
Factors of 36 = {1, 36}
= {1, 2, 18, 36}
= {1, 2, 3, 12, 18, 36}
= {1, 2, 3, 4, 9, 12, 18, 36}
= {1, 2, 3, 4, 6, 9,
12, 18, 36}
Following the same approach, we see that the factors of 96 are {1, 2, 3, 4, 6, 8,
12, 16, 24, 32, 48, 96}
When we examine both sets of factors, we see that the greatest common factor is
12 (i.e., x =
12)
What is the sum of the digits of x?
1 +
2 = 3
Answer: B
Cheers,
Brent
