document.write( "Question 1044198: Lottery ticket claimed that one in nine ticket win a prize.
\n" ); document.write( "a)what is the probability that you win at least twice when you purchase ten tickets
\n" ); document.write( "b)what is the approximate probability that you win more than 120times if you purchase 900 tickets?
\n" ); document.write( "c)Of all awarded prizes,10% are worth $1000,20% are worth %100 and 70% are worth $10.Find the expected winning if you purchase a single ticket.
\n" ); document.write( "

Algebra.Com's Answer #659475 by reviewermath(1029)\"\" \"About 
You can put this solution on YOUR website!
Q:Lottery ticket claimed that one in nine ticket win a prize.
\n" ); document.write( "a)what is the probability that you win at least twice when you purchase ten tickets
\n" ); document.write( "b)what is the approximate probability that you win more than 120times if you purchase 900 tickets?
\n" ); document.write( "c)Of all awarded prizes,10% are worth $1000,20% are worth %100 and 70% are worth $10.Find the expected winning if you purchase a single ticket.
\n" ); document.write( "Solution:
\n" ); document.write( "Let X = number of tickets that win a prize
\n" ); document.write( "a) X~Binomial(n = 10, p = 1/9)
\n" ); document.write( "\"P%28X+%3E=+2%29+=+1+-+P%28X+%3C=1%29\"
\n" ); document.write( "The formula using a TI calculator is
\n" ); document.write( "1-binomcdf(10, 1/9, 1).
\n" ); document.write( "The formula using Excel is
\n" ); document.write( "=1-BINOMDIST(1,10,1/9,TRUE)
\n" ); document.write( "The result to 4 decimal places is \"highlight%280.3071%29\"
\n" ); document.write( "b) X is approximately normal with mean 900(1/9) = 100 and variance
\n" ); document.write( "900(1/9)(8/9) = 800/9.
\n" ); document.write( "To correct for continuity, subtract 0.5 from X.
\n" ); document.write( "So the desired probability is P(X > 120.5).
\n" ); document.write( "Using a TI calculator, the formula is
\n" ); document.write( "=normalcdf(120.5, 99999, 100, (800/9)^0.5)
\n" ); document.write( "Using Excel, the formula is
\n" ); document.write( "=1-NORMDIST(120.5,100,(800/9)^0.5,TRUE)
\n" ); document.write( "The result is \"highlight%280.0148%29\"
\n" ); document.write( "c) The expected winning is =0.1*1000+0.2*100+0.7*10 = $\"highlight%28127%29\"
\n" ); document.write( "
\n" );