Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Probability Distributions

Question:

A box contains 10 balls, each marked with one of the digits 0 to 9. If four balls are drawn successively with replacement from the bag, then the probability that none is marked with the digit 0 is:

Options:

$(\frac{9}{10})^4$

$(\frac{1}{10})(\frac{9}{10})^3$

$(\frac{1}{10})^4$

$(\frac{1}{10})^2(\frac{9}{10})^2$

Correct Answer:

$(\frac{9}{10})^4$

Explanation:

The correct answer is Option (1) → $(\frac{9}{10})^4$

Total balls = $10$ (digits $0$ to $9$).

Probability of drawing a ball not marked $0 =$ $\frac{9}{10}$.

Since the draws are with replacement and four draws are made:

Required probability $=\left(\frac{9}{10}\right)^{4}$

$=\frac{6561}{10000}$