TS EAMCET · Maths · Probability
In a shelf there are three mathematics and two physics books. A student takes a book randomly. If he randomly takes, successively for three times by replacing the book already taken every time, then the mean of the number of mathematics books which is treated as random variable is
- A \(\frac{3}{2}\)
- B \(\frac{129}{125}\)
- C \(\frac{9}{5}\)
- D \(\frac{174}{125}\)
Answer & Solution
Correct Answer
(C) \(\frac{9}{5}\)
Step-by-step Solution
Detailed explanation
\( n=3, p=\frac{3}{3+2}=\frac{3}{5} \) \( E(X) = n \cdot p \) \( E(X) = 3 \cdot \frac{3}{5} \) \( E(X) = \frac{9}{5} \)
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