document.write( "Question 1100985: the probabaility that a car will have a flat tire while driving through a tunnel is 0.006. Find the probability that 2 of 5000 cars passing through the tunnel will have flat tires.\r
\n" ); document.write( "\n" ); document.write( "please help me with this.
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Algebra.Com's Answer #715570 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
this is a binomial probability type problem.\r
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\n" ); document.write( "\n" ); document.write( "the formula to use is p(x) = c(n,x) * p^x * q^(n-x)\r
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\n" ); document.write( "\n" ); document.write( "n is the total number of possible occurrences.
\n" ); document.write( "p is the probability that one occurrence happens.
\n" ); document.write( "q is the probability that one occurrence doesn't happen.
\n" ); document.write( "q is equal to 1 - p.
\n" ); document.write( "p^x is the probability of x occurrences happening.
\n" ); document.write( "q^(n-x) is the probability of (n-x) occurrences not happening.
\n" ); document.write( "c(n,x) is the number of ways you can get x occurrences out of n possible occurrences where order is not important.\r
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\n" ); document.write( "\n" ); document.write( "in your problem:
\n" ); document.write( "n is 5000.
\n" ); document.write( "x is equal to 2
\n" ); document.write( "n-x is equal to 5000 - 2 which is equal to 4998
\n" ); document.write( "p is equal to .006
\n" ); document.write( "q is equal to 1 - .006 = .994
\n" ); document.write( "c(5000,2) is equal to 12497500\r
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\n" ); document.write( "\n" ); document.write( "the formula of p(x) = c(n,x) * p^x * q^(n-x) becomes:\r
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\n" ); document.write( "\n" ); document.write( "p(2) = c(5000,2) * .006^2 * .994^4998\r
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\n" ); document.write( "\n" ); document.write( "c(5000,2) = 5000! / (2! * 4998!)
\n" ); document.write( "this is the same as c(5000,2) = (5000 * 4999 * 4998!) / (2! * 4998!)
\n" ); document.write( "the 4998! in the numerator and denominator cancel out and you are left with:
\n" ); document.write( "c(5000,2) = (5000 * 4999) / 2!
\n" ); document.write( "since 2! is equal to 2, then your answer becomes:
\n" ); document.write( "c(5000,2) = (5000 * 4999) / 2 and the result is:
\n" ); document.write( "c(5000,2) = 12497500.\r
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\n" ); document.write( "\n" ); document.write( "the formula of p(2) = c(5000,2) * .006^2 * .994^4998 becomes:
\n" ); document.write( "p(2) = 12497500 * .006^2 *.994^4998 which results in:
\n" ); document.write( "p(2) = 3.89291449 * 10^-11.\r
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\n" ); document.write( "\n" ); document.write( "that's a very small probability.\r
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\n" ); document.write( "\n" ); document.write( "in decimal notation, p(2) = .0000000000389291449\r
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