Aditi Mahajan

CAT Preparation Community 10y ago

Consider a triangle drawn on the X-Y plane with its three vertices at (41, 0), (0, 41) and (0, 0), each vertex being represented by its (X,Y) coordinates. The number of points with integer coordinates inside the triangle (excluding all the points on the boundary) is A 780 B 800 C 820 D 741 The number of points on x = 1 is 39. The number of points on x = 2 is 38 and so on till x = 39, which has one point. So, the total is 1+2+3+...+39 = 39∗40239∗402 = 780.