Veritas Prep
If Jesse flips a coin seven times in a row, what is the probability that the result will be heads at least five times?
A. \(21/128\)
B. \(29/128\)
C. \(35/128\)
D. \(1/16\)
E. \(1/4\)
OA B
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If Jesse flips a coin seven times in a row, what is the probability that the result will be heads at least five times?
This topic has expert replies
Probability to get at least \(5\) heads in \(7\) flips.
The total outcome of flip is \(= 2^7 = 128\)
For any Coins problem write the ask in the shown format.
\(HHHHHTT\)
\(HHHHHHT\)
\(HHHHHHH\)
Once you have written in the above mentioned format the answer is pretty straight.
\(HHHHHTT = \dfrac{7!}{5! \cdot 2!} = 21\)
\(HHHHHHT = \dfrac{7!}{6!} = 7\)
\(HHHHHHH = \dfrac{7!}{7!} = 1\)
Sum \(= 21+7+1 = 29/128\)
Therefore, B
