In the previous question if a prticular student Amit came with Rohit but not with shyamu then find the number of ways to select 4 students out of 10 students

(Q). In the previous question if a prticular student Amit came with Rohit but not with shyamu then find the number of ways to select 4 students out of 10 students.
Solution:-
Number of ways = ¹⁰⁻²⁻¹C₄₋₂
                               = ⁷C₂
                               = 21    Solution