document.write( "Question 1001201: Question from Binomial Probability
\n" ); document.write( "If three coins are tossed, find the probability of each number of heads.
\n" ); document.write( "4) 3
\n" ); document.write( "5) 1 or 2
\n" ); document.write( "6) at least 1\r
\n" ); document.write( "\n" ); document.write( "According to the book, For number 5 the answer is 3/4.
\n" ); document.write( "would like to see solutions shown for all three. Thanks.
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Algebra.Com's Answer #618443 by rothauserc(4718)\"\" \"About 
You can put this solution on YOUR website!
The binomial probability formula is
\n" ); document.write( "P(k successes in n trials) = nCk * p^k * q^(n-k) where
\n" ); document.write( "n = number of trials
\n" ); document.write( "k = number of successes
\n" ); document.write( "n-k = number of failures
\n" ); document.write( "p = probability of success in one trial
\n" ); document.write( "q = 1 – p = probability of failure in one trial
\n" ); document.write( "nCk = combination of n trials taken k at a time
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\n" ); document.write( "for our problem
\n" ); document.write( "n = 3
\n" ); document.write( "p = 0.50
\n" ); document.write( "q = 0.50
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\n" ); document.write( "4) 3 successes
\n" ); document.write( "P(3 successes in 3 trials)= 3C3 * (0.50)^3 * (0.50)^(3-3) =
\n" ); document.write( "(3! / (3! * (3-3)!) * (0.125) * 1 =
\n" ); document.write( "0.125
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\n" ); document.write( "5) first calculate
\n" ); document.write( "P(0 successes in 3 trials) = 3C0 * (0.50)^0 * (0.50)^(3-0) =
\n" ); document.write( "(3! / (0! * (3-0)!) * 1 * (0.125) =
\n" ); document.write( "0.125
\n" ); document.write( "therefore
\n" ); document.write( "P(1 or 2 successes in 3 trials) = 1 - (P(3 successes in 3 trials) + P(0 successes in 3 trials)) =
\n" ); document.write( "1 - (0.125 + 0.125) = 0.75 = 3/4
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\n" ); document.write( "6) note that
\n" ); document.write( "P(at least 1 success in 3 trials) = 1 - P(0 successes in 3 trials) =
\n" ); document.write( "1 - 0.125 = 0.875
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