There are totally 10 balls - 2R + 3B + 5 W
Hence, the total number of possible combinations when 3 balls are drawn out of 10 balls = 10 C 3
There are 3 B balls. Hence, the total number of possibilities of getting 3 B out of 3 balls = 3 c 3 = 1
Hence, the required probability=1(10 C 3)=1120