There are total 9 balls in which 3 balls are white and 6 balls are red. Total number of observation =‌9C4 Number of favourable outcomes =(2 Red 2 Black +3 Red ×1 Black +4 Red) balls =‌6C2×‌3C2+‌6C3×‌3C1+‌6C4 P (atleast two red balls) ‌=‌