A box contains 10 balls out of which 3 are red and rest are blue. In how many ways can a random sample of 6 balls be drawn from the bag so that at the most 2 red balls are included in the sample and no sample has all the 6 balls of the same colour?
A. 105
B. 168
C. 120
D. 189
Answer: Option B
Solution(By Examveda Team)
Six balls can be selected in the following ways: One red ball and 5 blue ball Or Two red balls and 4 blue balls. Total number of ways: = (3C1 × 7C5) + (3C2 × 7C4)= 63 + 105
= 168
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Comments ( 1 )
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Really it's very helpful