Combinatorics Problem from OG-11

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Combinatorics Problem from OG-11

by rabab » Sat Oct 18, 2008 7:21 am
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 inequalities -4<=x<=5 and 6<=y<=16. How many different triangles with these properties could be constructed.

(a) 110
(b) 1,100
(c) 9,900
(d) 10,000
(e) 12,100

Please explain in details.
Source: — Problem Solving |