<PRE><B>Question 159742</B>
The directions say,&quot;In exercise 2, consider a 10-question true/false test.&quot; The question is, &#39;How many ways are there to score exactly 80%? That is, how many ways are there to get exactly 2 questions wrong? Explain why choosing which questions you will get wrong determines all your answers.
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True/False questions are binomial because there are only two possible answers.
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2 wrong out of 10 is the same as 8 right out of 10
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Ans: # of ways to select 2 from 10 is 10C2 = [10*9]/[1*2] = 45
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Cheers,
Stan H.</PRE>