VJesus12 wrote:Is xy < 10?

(1) x < 5 and y < 2
(2) x < −3 and y < −1

The OA is the option E.

Could anyone explain this DS question to me? Please. I'd like to know how can I solve it. <i class="em em-confused"></i>

We have to determine whether xy < 10.

Let's understand this inequality better.

1. If xy < 0, i.e. xy is negative, the answer is Yes.

For xy < 0, one of x and y must be positive and the other must be negative.

2. If xy = 0, the answer is Yes.

For xy = 0, At least one of x and y must be 0.

3. If 0 < xy < 10, i.e. xy is positive but less than 10, the answer is Yes.

Let's see each statement one by one.

(1) x < 5 and y < 2

Case 1: Say x = y = -10

=> xy = -10*-10 = 100 > 10, the answer is No.

Case 2: Say x = -4 and y = -2

=> xy = -4*-2 = 8 < 10, the answer is Yes.

No unique answer. Insufficient.

(2) x < −3 and y < −1

Both the cases discussed above are applicable here too. Insufficient

(1) and (2) together

Both the cases discussed above are applicable here too. Insufficient

The correct answer: E

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: Manhattan Review India | Hyderabad GMAT Coaching | Bangalore GMAT Courses | Visakhapatnam | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.