Question

A bag contains 4 blue, 5 red and 7 green balls. If 4 balls are drawn one by one with replacement, what is the probability that all are blue?

• A. $\frac{1}{16}$
• B. $\frac{1}{4}$
• C. $\frac{1}{256}$
• D. $\frac{1}{64}$

Answer 1

The correct option is C $\frac{1}{256}$

Probability of drawing a blue ball=$\frac{4}{4+5+7}$=$\frac{4}{16}$=$\frac{1}{4}$

$\therefore$Required probability=$\frac{1}{4}\times \frac{1}{4}\times \frac{1}{4}\times \frac{1}{4}\times \frac{1}{4}=\frac{1}{256}$.