题目内容

两个同学做同一道数学题,他们做对的概率分别是0.8和0.9,则该题至少被一个同学做对的概率是
A.0.72B.0.83C.0.7D.0.98
D
本题考查概率
两个同学做同一道数学题,他们做对的概率分别是0.8和0.9,而这两个事件的相互独立的,则他们不能做对的概率分别为,则他们都不能做对的概率为,至少被一个同学做对的概率与两人都不能做对是对立事件,则所求的概率为。故正确答案为D
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