A bag 4

A bag contains 18 balls that differ only in color, 11 are blue, and seven are red. If two balls are picked, one after the other without replacement, find the probability that both are
(i) Blue
(ii) Of the same color
(iii) Of different colors

Correct answer:

a =  0.3595
b =  0.4967
c =  0.5033

Step-by-step explanation:

$a=\frac{11}{18}\cdot \frac{10}{17}=\frac{11\cdot 10}{18\cdot 17}=\frac{110}{306}=\frac{55}{153}=0.3595$

$b=\frac{11}{18}\cdot \frac{10}{17}+\frac{7}{18}\cdot \frac{6}{17}=\frac{76}{153}=0.4967$

$c=1-b=1-\frac{76}{153}=\frac{1\cdot 153}{153}-\frac{76}{153}=\frac{153}{153}-\frac{76}{153}=\frac{153-76}{153}=\frac{77}{153}=0.5033$

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