第1点随机事件的概率(★★★)必做1袋子中放有大小和形状相同的小球若干,其中标号为0的小球1个,标号为1的小球1个,标号为2的小球n个,已知从袋子中随机抽取I个小球,取到标号为2的小球的概率是I/2.(1)求n的值;(2)从袋子中不放回地随机抽取2个球,记第一次取出的小球标号为a,第二次取出的小球标号为b.1记“a+b=2”为事件A,求事件A的概率;2在区间[0,2]内任取实数x,y The probability of the first random event (★ ★ ★) must be done 1 bag placed in the same size and shape of a number of small balls, including a small ball labeled 0, a small ball labeled 1, labeled 2 Of the n pellets, it is known that the probability of taking one pellet randomly from the bag and taking the pellet labeled as 2 is I / 2. (1) Find the value of n; (2) Return from the bag 2 randomly selected ball, remember the first ball was removed marked a, the second ball removed marked b.1 remember “a + b = 2 ” for the event A, the probability of seeking the event A ; 2 in the interval [0,2] to take the real number x, y