The fastest approach is probably to just list the factors of 42 and 56swerve wrote:How many factors of 42 are not factors of 56?
A. 1
B. 2
C. 3
D. 4
E. 5
Factors of 56: {1, 2, 4, 7, 8, 14, 28, 56}
Factors of 42: {1, 2, 3, 6, 7, 14, 21, 42}
So, the factors of 42 that are NOT factors of 56 are: 3, 6, 21 and 42 (four numbers in total)
Answer: D
Cheers,
Brent
