Multiple choice

A box contains six red balls and four green balls. Four balls are selected at random from the box. What is the probability that out of the selected balls, two will be red and two will be green?

  1. 1/7

  2. 2/7

  3. 3/7

  4. 4/7
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total ways to pick 4 balls from 10 = 10C4 = 210. Favorable ways = (6C2) * (4C2) = 15 * 6 = 90. Probability = 90 / 210 = 9 / 21 = 3 / 7.

AI explanation

The box contains 10 balls in total, so the total number of ways to draw 4 balls is 10C4, which equals 210. The number of ways to choose exactly 2 red balls from the 6 available is 6C2, which equals 15, and the number of ways to choose exactly 2 green balls from the 4 available is 4C2, which equals 6. The total number of favorable outcomes is the product of these combinations, 15 times 6, giving 90. The probability is the favorable outcomes divided by the total outcomes, which is 90/210, and this fraction simplifies to 3/7. The probability that two will be red and two will be green is 3/7.

Keep practicing — related questions