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Re: A biased coin's probability of landing on head is 2/5. [#permalink]
1
Given that A biased coin's probability of landing on head is 2/5 and we need to find What is the probability of getting at least 1 tail, when the coin is flipped 4 times?

P(At least 1 Tail) = 1 - P(0 Tail) (As P(0 Tail) + P(At least 1 Tail) = Total Probability = 1 )
= 1 - P(HHHH) = 1 - \(\frac{2}{5}\) * \(\frac{2}{5}\) * \(\frac{2}{5}\) * \(\frac{2}{5}\)
= 1 - \(\frac{16}{625}\)
= \(\frac{625 - 16}{625}\)
= \(\frac{609}{625}\)

So, Answer will be D
Hope it helps!

Watch the following video to learn How to Solve Probability with Coin Toss Problems

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Re: A biased coin's probability of landing on head is 2/5. [#permalink]
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