# Easy Probability Solved QuestionAptitude Discussion

 Q. A bag contains 7 green and 5 black balls. Three balls are drawn one after the other. The probability of all three balls being green, if the balls drawn are not replaced will be:
 ✖ A. 343/1728 ✖ B. 21/36 ✖ C. 12/35 ✔ D. 7/44

Solution:
Option(D) is correct

Here, $n(E)$$=^7C_1\times ^5C_1\times ^5C_1$

And, $n(S)$$=^{12}C_1\times ^{11}C_1\times ^{10}C_1$

$P(S)=\dfrac{7\times6\times5}{12\times11\times 10 }$

$=\dfrac{7}{44}$

## (1) Comment(s)

P V Gopalakrishnan
()

It should be 7c1X6c1x5c1