Multiple choice

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 1st one is red and the second one is black is

  1. $\displaystyle \frac{30}{121}$
  2. $\displaystyle \frac{60}{121}$
  3. $\displaystyle \frac{36}{221}$
  4. $\displaystyle \frac{36}{121}$
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A Correct answer
Explanation

Total balls = 11. Probability of red = 6/11. Probability of black = 5/11. Since it is with replacement, the events are independent. Probability = (6/11) * (5/11) = 30/121.

AI explanation

The bag has 11 total balls, so the probability of drawing a red ball first is 6/11. Because the first ball is replaced, the probability of drawing a black ball second is 5/11. By the multiplication rule for independent events, the combined probability is 6/11 multiplied by 5/11, which equals 30/121.

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