Question

There are 6 red and 5 black balls in a bag. Two balls are drawn at random one after another with replacement. The probability that one is red and one is black is

• A. $\frac{30}{121}$
• B. $\frac{60}{121}$
• C. $\frac{36}{121}$
• D. $\frac{36}{221}$

Answer 1

The correct option is B $\frac{60}{121}$

A bag contains: $6R+5B=11$
Probability of getting $1R+1B$ and $1B+1R$ ball from this bag with replacement:
$=\left[\right(\frac{6}{11})\times (\frac{5}{11}\left)\right]+\left[\right(\frac{5}{11})\times (\frac{6}{11}\left)\right]=\frac{60}{121}$