An urn contains 6 red, 5 blue and 2 green marbles. If three marbles are picked at random, what is the probability that at least one is blue?
A. $$\frac{{28}}{{143}}$$
B. $$\frac{{115}}{{97}}$$
C. $$\frac{{28}}{{197}}$$
D. $$\frac{{115}}{{143}}$$
Answer: Option D
Solution (By Examveda Team)
P(None is blue),$$\eqalign{ & = \frac{{^8{C_3}}}{{^{13}{C_3}}} \cr & = \frac{{56}}{{286}} \cr & = \frac{{28}}{{143}} \cr} $$
P(At least one is blue),
$$\eqalign{ & = 1 - \frac{{28}}{{143}} \cr & = \frac{{115}}{{143}} \cr} $$
This Question Belongs to Arithmetic Ability >> Probability
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