An urn initially contains 2 balls, one of which is red and the other blue. At each stage a ball is randomly selected. If the sel
ected ball is red, then it is replaced with a red ball with probability .7 or with a blue ball with probability .3; if the selected ball is blue, then it is equally likely to be replaced by either a red or blue ball.
An urn initially contains one red and one blue ball. At each stage, a ball is randomly chosen and then replaced along with another of the same color. Let X denote the selection number of the first chosen ball that is blue. For instance, if the first selection is red and the second blue, then X is equal to 2.
The first statement is true. The second statement is false. The imperfect tense is setting up for something to happen. The last statement is false. The preterit tense is used to describe something that happened in the past.
