boomgoesthegmat wrote:The positive two-digit integers x and y have the same digits, but in reverse order. Which of the following must be a factor of x + y?
A) 6
B) 9
C) 10
D) 11
E) 14
OA: D
The question asks is to find what
MUST be true.
So, a quick and simple solution is to TEST some values. If a statement turns out to be FALSE, we can eliminate that answer choice.
Let x = 12 and let y = 21
So, x + y = 12 + 21 = 33
Now check the answer choices.
A) 6 is
not a factor of 33. ELIMINATE A
B) 9 is
not a factor of 33. ELIMINATE B
C) 10 is
not a factor of 33. ELIMINATE C
D) 11
IS a factor of 33. KEEP D
E) 14 is
not a factor of 33. ELIMINATE E
Answer:
D
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
