In a win-win lottery, the two reels contain well-mixed red and blue balls. In the first – 70 red and 30 blue

In a win-win lottery, the two reels contain well-mixed red and blue balls. In the first – 70 red and 30 blue; in the second 20 red and 40 blue. One ball is taken out at random. It turned out to be red. Determine the probability that the ball was removed from the second reel.

The probability that a red ball is removed from the second reel is 20/60 = 1/3.

And the probability that the ball is taken out of the second reel, and not from the first, is equal to:

(20 + 40): (70 + 30 + 20 + 40) = 60/160 = 3/8.

Then, in order to determine the probability that the red ball is removed from the second reel, you need to multiply the probabilities found above:

1/3 * 3/8 = 1/8.

Answer: 1/8.