Bunuel wrote:

abdullaiq wrote:

Could someone please explain how those numbers came out? Where did the 11, 10, and 9 came from? There is no specific point for them.

gettinit wrote:

yes can someone please explain in detail please? Thanks

Right triangle PQR is to be constructed in the xy-plane so that the right angle is at P and PR is parallel to the x-axis. The x and Y coordinates of P,Q and R are to be integers that satisfy the inequalitites -4≤ X≤ 5 and 6≤ y≤ 16. How many different triangles with these properties could be constructed?A. 110

B. 1100

C. 9900

D. 10000

E. 12100

We have the rectangle with dimensions 10*11 (10 horizontal dots and 11 vertical). PQ is parallel to y-axis and PR is parallel to x-axis.

Choose the (x,y) coordinates for vertex P (right angle): 10C1*11C1;

Choose the x coordinate for vertex R (as y coordinate is fixed by A): 9C1, (10-1=9 as 1 horizontal dot is already occupied by A);

Choose the y coordinate for vertex Q (as x coordinate is fixed by A): 10C1, (11-1=10 as 1 vertical dot is already occupied by A).

10C1*11C1*9C1*10C1=9900.

Answer: C.

Other discussion with alternate solutions:

http://gmatclub.com/forum/arithmetic-og ... ed#p790651http://gmatclub.com/forum/geometry-and- ... ed#p777591http://gmatclub.com/forum/700-question- ... ed#p818546Hope it helps.

Hi Bunuel i would to take this question as an opportunity to ask you few questions. Today i have formally started my preparation for quant i have read all MGMT maths books and Gmat club math book my concepts are fine and this is my first 700+ and

oG tag question but the real problem i am facing is the time management such as in this question i was unable to find a concrete procedure and it took me 5 min to sort the matter out and find discreetly what the question was asking. i would like to know that is there any specific pattern in quants that keep on repeating in a different creative way so that one dont waste time sorting out the method but rather recognize the pattern and slove it. just like the chess puzzle or i would put it in another way, how solving this question is helping me in quant practice. Furthermore should i practice 700+ questions only or should i go for 600-700 range as well.

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