Which of the following could be the greatest common factor of positive integers a and b?
I. 1
II. a
III. a-b
A) II only
B) I and II only
C) I and III only
D) II and III only
E) I, II and III
The OA is E.
I don't know how can I solve this PS question. I need some help. Thanks.
Which of the following could be the greatest . . .
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Hi Vincen,
We're told that A and B are positive integers. We're asked which of the Roman Numerals COULD be the Greatest Common Factor of A and B. We can solve the problem by TESTing VALUES.
I. 1
IF A=1 and B=2, then the GCF = 1. Roman Numeral 1 COULD be true.
Eliminate Answers A and D.
II. A
IF A=1 and B=2, then the GCF = 1 (so the GCF = A). Roman Numeral 2 COULD be true.
Eliminate Answer C.
III. A - B
IF A=2 and B=1, then the GCF = 1 (so the GCF = A-B). Roman Numeral 3 COULD be true.
Eliminate Answer B.
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
We're told that A and B are positive integers. We're asked which of the Roman Numerals COULD be the Greatest Common Factor of A and B. We can solve the problem by TESTing VALUES.
I. 1
IF A=1 and B=2, then the GCF = 1. Roman Numeral 1 COULD be true.
Eliminate Answers A and D.
II. A
IF A=1 and B=2, then the GCF = 1 (so the GCF = A). Roman Numeral 2 COULD be true.
Eliminate Answer C.
III. A - B
IF A=2 and B=1, then the GCF = 1 (so the GCF = A-B). Roman Numeral 3 COULD be true.
Eliminate Answer B.
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
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Let's analyze each Roman numeral.Vincen wrote:Which of the following could be the greatest common factor of positive integers a and b?
I. 1
II. a
III. a-b
A) II only
B) I and II only
C) I and III only
D) II and III only
E) I, II and III
I. 1
If a = 4 and b = 7, then their greatest common factor is 1. So I is possible.
II. a
If a = 4 and b = 8, then their greatest common factor is 4, which is a. So II is possible.
III. a - b.
If b = 8 and a = 4, then their greatest common factor is 4, which is a - b. So III is possible.
Answer: E
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