You have 100 coins. One coin is two-headed, and the other 99 are fair coins. You randomly select a coin and flip it 10 times, observing heads on all 10 flips. What is the probability that the coin you selected is the two-headed coin?

有100个硬币，1个双面都是正面，99个是公平硬币。随机选一个扔10次都是正面，这个硬币是双面正的概率是多少?