If a and b are integers such that a > b > 1, which of the following cannot be a multiple of either a or b?
(A) a - 1
(B) b + 1
(C) b - 1
(D) a + b
(E) ab
I understand why (b-1).[Logically it is absolutely right] but it doesn’t seem to follow when a=8 b=5 or a=20,b=15, for that matter. Please correct me if I’m wrong.
Thank you in advance!
a = 8 , b =5
C = b-1 = 5-4 =4
Multiple of 8 = 8 ,16,24 etc .
Now, 4 is not a multiple of 8, 8 is a multiple of 4 and questioned asked multiple of (for our case: a=8or b=5)
Multiple of 4 = 4,8,12 etc
Yeah, true! but option D) a+b =8+5 =13 isn’t multiple of either a or b. so I thought that could have been an anomaly. I think they should have used MUST NOT instead of CANNOT ?