275概率中等derivationmedium
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题目
A fair coin is flipped repeatedly. What is the expected number of flips until first appears?
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提交作答时记录，用于后续平均用时统计。
你的答案
题目
A fair coin is flipped repeatedly. What is the expected number of flips until first appears?
解题计时
0:00
提交作答时记录，用于后续平均用时统计。
你的答案