4

Part of 1994 India National Olympiad

Problems(1)

Find the no. of triangles

Source: INMO 1994 Problem 4

Find the number of nondegenerate triangles whose vertices lie in the set of points

(s,t)

in the plane such that

0 \leq s \leq 4

0 \leq t \leq 4

s

t

combinatorics unsolvedcombinatorics