BTGmoderatorDC wrote:Set X consists of different positive numbers arranged in ascending order: K, L, M, 5, 7. If K, L and M are consecutive integers, what is the arithmetic mean of set X?
(1) The product KLM is a multiple of 6
(2) There are at least 2 prime numbers among K, L and M
Target question: What is the arithmetic mean of set X?
Given: Set X consists of different positive numbers arranged in ascending order: K, L, M, 5, 7. K, L and M are consecutive integers
This means that
EITHER K, L, M = 1, 2, 3 respectively, OR K, L, M = 2, 3, 4 respectively
Head straight to.....
Statements 1 and 2 combined
Notice that the
two cases above satisfy BOTH statements. That is:
Case a: K, L, M = 1, 2, 3 respectively. In this case, the arithmetic mean of set X = (1+2+3+5+7)/5 = 18/5. So, the answer to the target question is
18/5
Case b: K, L, M = 2, 3, 4 respectively. In this case, the arithmetic mean of set X = (2+3+4+5+7)/5 = 21/5. So, the answer to the target question is
21/5
Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer: E
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
