Question

There are 10 points on a line and 11 points on another line, which are parallel to each other. How many triangles can be drawn taking the vertices on any of the line?

• A. 1050
• B. 2550
• C. 150
• D. 1045

Answer 1

The correct option is D 1045

For a triangle, two points on one line and one on the other has to be chosen.
No. of ways $={}^{10}{C}_2\times {}^{11}{C}_1+{}^{11}{C}_2\times {}^{10}{C}_1=1,045$.