關於probability的簡單Maths.問題(2)

Tieria

2009-10-03 7:24 am

1. A card is drawn at random from a pack of 52 playing cards and then replaced before a second card is drawn at random. Find the probability that the first card is a club or a heart while the second card is a face card (i.e. J, Q or K).

The answer is 3 / 26.

2. The probability that Vincent will win a game in a table tennis match is 0.6. He joins the school inter-class table-tennis competition. The game rule requires that at most three games will be played by each player and the player who wins any two games will win the match. Find the probability that Vincent wins this match.

Do you think the above game rule or the one-game match (i.e. one game to determine win or lose) is more advantageous to Vincent?

The answer is 0.648, ‘best of three games’.

※請列明計算步驟※

回答 (1)

用戶2053

2009-10-03 7:56 am

✔ 最佳答案

1)P(the first card is a club or a heart )
= 1/2
P(the second card is a face card (i.e. J, Q or K).)
= 3/13
P(E) = 1/2 * 3/13 = 3/26
2)P(Vincent wins this match.)
= P(win 3 games) + P(win 2 games lose 1 game)
= 0.6^3 + (0.6^2)(1 - 0.6)*3C2
= 0.648
Do you think the above game rule or the one-game match (i.e. one game to determine win or lose) is more advantageous to Vincent?
No. Since 0.648 (for 3 games) > 0.6 (for 1 game)

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