Gaokao Math Practice Question
6. （5 分) 某种种子每粒发芽的概率都为 0.9 , 现播种了 1000 粒, 对于没有发 芽的种子, 每粒需再补种 2 粒, 补种的种子数记为 $X$, 则 $X$ 的数学期望为 $(\quad)$
- A.100
- B.200
- C.300
- D.400
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