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標題:
概率...快快"
發問:
1,國華玩拋代幣遊戲,規則規定参與者把一個半徑2cm的代幣拋到邊長為8cm的正方形"次"塼密鋪平面上,若代幣完全落到一塊次塼之上就為勝,求國華拋擲一次而獲勝的概率2,投擲一枚不匀稱的骰子,得單數點and雙數點的概率分別為p and q,其中p:q=2:3a,求p and q值b,若投擲兩枚相同骰子 a,求取得兩個單數點的概率 b.求取得一單數點and 一雙數點的概率 ... 顯示更多 1,國華玩拋代幣遊戲,規則規定参與者把一個半徑2cm的代幣拋到邊長為8cm的正方形"次"塼密鋪平面上,若代幣完全落到一塊次塼之上就為勝,求國華拋擲一次而獲勝的概率 2,投擲一枚不匀稱的骰子,得單數點and雙數點的概率分別為p and q,其中p:q=2:3 a,求p and q值 b,若投擲兩枚相同骰子 a,求取得兩個單數點的概率 b.求取得一單數點and 一雙數點的概率 c.求取得兩個雙數點的概率 3,某班學生人數多於30,少於40,女生數目剛好較男生多20% a,求女生的數目 b,若班中隨機抽兩位學生,得一位男生and一位女生的概率是多少? 4,某次測驗,共有題目3條,每條計分法如下,答對1分,答錯0分.若某甲答對任何一條的概率都是0.6,求下到概率 a,某甲該次測驗得3分 b.在該次得0分 c,在該次得1分 d,在該次得2分 請詳細列明步驟...thx alot
最佳解答:
1) Let the center of the coin be C, player will win if C is at least 2cm away from all 4 sides of the square it lies Within a 8cm x 8cm square, C is 2cm away from each side when it lies within the 4cm x 4cm zone in the centre of the 8cm x 8cm square (try to draw out the graph and you'll see!) Since the coin have equal chance to land on anywhere within any square, probability players will win = area of the 4cm x 4cm square (win zone) / area of the 8cm x 8cm square (possible zone) = 16 / 64 = 1 / 4 2) (a) since p + q = 1 and p:q = 2:3 on solving, p=0.4 and q=0.6 (b) Since two throw of dices are independent of each other, Prob(both dice shows odd outcome) = Prob(a dice shows odd outcome)^2 = p^2 = 0.16 Similarly, Prob(both dices shows even outcome) =q^2 = 0.36 Prob(one show odd and one show even) = 1 - 0.16 - 0.36 = 0.48 3) (a) Let number of boys be x, so number of girls is 1.2x since 30
其他解答:
1) (2 X 2 X 3.14) /8 X 8 ~19.6 2) P=2/2+3 =0.4 Q=3/2+3 =0.6DF665233EBFAA7EC
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