popew626 wrote:

A deck of cards contains 2 blue cards and 5 red cards. A card is randomly selected from the deck. Whatever color card is selected, a card of the other color is inserted into the deck. For instance, a blue card is drawn and a red card is reinserted in the deck. If another card is now selected, what is the probability that the card is red?

A. 6/7

B. 11/15

C. 32/49

D. 4/7

E. 12/49

Probabiliy of selecting Red = 5/7 and Blue = 2/7

5/7 probability that the next set will be 3 Blue and 4 Red (in which case probabilityof red is 4/7

2/7 probability taht the next set will be 1 Blue and 6 Red (in which case the probability of red is 6/7

so the overall probability of red is (5/7*4/7)+(2/7*6/7) =

32/49 _________________

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