in a certain circle there are 9 points . what is the number of the triangles connecting 3 points of the 9 points ?
"imo : b here we have to select 3 points out of 9 points . order is not important so the answer will be 9 c 3 = 84 answer b"
divide(factorial(9), multiply(factorial(divide(const_10, const_2)), factorial(3)))