Hi Jitsy,
Great job noticing that numbers such as square roots should also be considered in the explanation to this question. I submitted your question/comment to our editorial team who manages our Random House titles and has an email address so that readers can report errata and problems (
[email protected]). Some books, including Cracking the GMAT, have online lists of known errata as part of the online entitlements for those books. Editorial also maintains lists of reported/known errata and the update process for books always starts with a review of those known problems.
So they'd like to confirm that the answer is (E) and we'll get the explanation updated for the next edition of the book - again thank you. And here is the answer explanation from our team:
(E) To answer this yes-no question, plug in. Start by choosing two numbers that satisfy statement (1). For example, x = 2 and y = 3 satisfy statement (1) because 2 × 3 = 6 which is an integer. The answer to the question "are x and y integers?" is 'yes' for these numbers. Next, pick new numbers that satisfy the statement but try to get an answer of 'no' to the question. If x = -√2 and y = √2, statement (1) is satisfied because the product of x and y is −2, an integer. However, the answer to the question is now 'no'. Since it's possible to get both an answer of 'yes' and an answer of 'no' with numbers that satisfy the statement, statement (1) is insufficient and the possible answers are (B), (C) and (E). Next, pick numbers that satisfy statement (2). Both sets of numbers that satisfied statement (1) also satisfy statement (2). So, it's possible to find numbers that produce both an answer of 'yes' and an answer of 'no' for statement (2). Hence, statement (2) is insufficient, so eliminate (B). Since these numbers satisfy both statements, it also means that the combined statements are insufficient. The answer is (E).
jitsy wrote:Thanks a lot! Really appreciate your detailed explanation.
However, if you consider √2 and -√2 to be X and Y respectively, both statement 1) and statement 2) are satisfied [√2*(-√2) = -2 which is an integer and √2 + (-√2) = 0 which is also an integer]. And of course, √2 and -√2 are not integers.
Please let me know if this is not correct.
Thanks again.
