数学题目 曼哈顿上的

ivydorian

In United States currency, a nickel is worth 5 cents, a penny is worth 1 cent, and a dime is worth 10 cents. 100 cents equals one dollar. If a hand purse contains 6 nickels, 5 pennies and 4 dimes, what is the probability of picking a coin other than a nickel twice in a row if the first coin picked is not put back?

sunflowerljn

答案是什么？

ivydorian

我也想知道  有人会吗

yuanshihyu

我算是12/35總共15個硬幣，6個nickle，9個非nickle
連續取兩個非nickle，取出不放回，則第一次取機率為9/15，再乘上第二次取的機率8/14
(9/15)*(8/14)=12/35

sunflowerljn

嗯嗯 我觉着也是楼上的答案 但是不确定