Subject: check secondary worksheet I was wondering if you could let me know if I did these problems correctly, and if not can you let me know how to fix them, thanks Dee. A card is selected from an ordinary deck of cards. What is the probability of. . . selecting 2 aces in a row? i got .036038961 and If you toss two dice, what would be your probability of the following?
thanks Hi Dee,The answer to the first question depends on how you draw the two cards. If you are selecting one card from a standard deck the probability of it being an ace is 4/52 = 1/13. If you got an ace and then select a second card the probability that it is an ace is 3/51. (There are only 51 cards left and only 3 aces.) Thus the probability that both are aces is 1/13 x 3/51. If you are to put the first ace back in the deck before you draw the second card then the probability that the second card is an ace is also 4/52. In this case the probability of two aces is (4/52)^{2}. For the dice problem you should make a 6 by 6 chart of all the 36 possibilities of the result of tossing two dice, think of them as Red and Green. 1 2 3 4 5 6 1 (1,1) (1,2) (1,3) (1,4) (1,5) (1,6) 2 (2,1) (2,2) (2,3) (2,4) (2,5) (2,6) 3 (3,1) (3,2) (3,3) (3,4) (3,5) (3,6) . . . . . . . . . . . . . . Looking at the table above I also got 5/36 for the first part. You can get a sum of six from (5,1), (4,2) (3,3), (2,4) and (1,5). Now can you do the rest? Penny
