Is xy

Question

Is xy < 17 ?
 
(1) x < 0 and y > 0.
(2) x ≤ 3 and 2 ≤ y ≤ 5.

GMATinsight · Answer

Question : Is xy < 17?

Statement 1 : x < 0 and y > 0. 
Since x is negative and y is positive hence, xy will always be negative hence
SUFFICIENT

Statement 2 : x ≤ 3 and 2 ≤ y ≤ 5 
The maximum value of xy will be when x is 3 and y is 5
i.e. Maximum xy = 15 which is less than 17, Hence
SUFFICIENT

Answer: Option D

awdxzs · Answer

Ans is A
As from statement 1 
x is negative and y is positive so xy<0 which is less than 17
But from statement 2
x can be positive or negative while y is always positive so not sufficient.

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akhiparth · Answer

Ans D
1 is sufficient as obvious.
2 shows max positive value of x is 15. sufficient.

ccooley · Answer

Go a little further with the cases you tested for statement 2. The error you've made here is a classic one: assuming that something is insufficient, without actually writing out the specific cases that show it's insufficient. Here, if you write out the cases, here's what happens: Case 1: x = 2 y = 3 xy = 6 which is less than 17, so the answer is 'yes' Case 2: x = -100 y = 3 xy = -300 which is less than 17, so the answer is 'yes' It's true that xy can be either positive or negative, but both the positive and negative answers actually give you the same answer to the question asked. All negative numbers are smaller than 17, after all.

Is xy < 17 ? (1) x < 0 and y > 0. (2) x ≤ 3 and 2 ≤ y ≤ 5.

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