Suppose an urn contains 8 red,5 white and 7 blue marbles.a.If 3 marbles are drawn at random from the urn with replacement,what is the probability that three marbles are red?
(8/20)^3
To find the probability of drawing three red marbles with replacement from the urn, we need to determine the probability of drawing one red marble with replacement and multiply it by itself three times.
The probability of drawing a red marble with replacement can be found by dividing the number of red marbles by the total number of marbles in the urn.
Given that there are 8 red marbles, 5 white marbles, and 7 blue marbles, the total number of marbles in the urn is 8 + 5 + 7 = 20.
Therefore, the probability of drawing a red marble with replacement is 8/20 = 2/5.
Since we are drawing with replacement, each draw is independent. So, to find the probability of drawing three red marbles, we multiply the probability of drawing one red marble by itself three times.
(2/5) * (2/5) * (2/5) = 8/125.
Hence, the probability of drawing three red marbles with replacement is 8/125.