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
A) 6
B) 9
C) 10
D) 11
E) 14
OA: D
The question asks is to find what MUST be true.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
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
