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magical cook
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 Posted: Wed Nov 28, 2007 10:51 am Post subject: PS 14 |
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C(m,n) = m! / [(m-n)! n!] for nonnegative integers m and n, m ³ n. If C(5,3) = C(5,x) and x ¹
3, what is the value of x?
A. 0
B. 1
C. 2
D. 4
E. 5
Hi, somehow I got it wrong. hope someone could help... |
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gabriel
Managing Director
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Location: India
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| Posted: Thu Nov 29, 2007 2:41 am Post subject: Re: PS 14 |
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| magical cook wrote: | C(m,n) = m! / [(m-n)! n!] for nonnegative integers m and n, m ³ n. If C(5,3) = C(5,x) and x ¹
3, what is the value of x?
A. 0
B. 1
C. 2
D. 4
E. 5
Hi, somehow I got it wrong. hope someone could help... |
According to the given information C(5,3)= 5!/(3!*2!) ... and C(5,x) = 5!/((5-x)!*x!) .. now if you compare the 2 denominators you will see that only x = 2 will give the values 3 and 2 (which is what we want if they have to be equal) in the denominator, so the answer is C, that is x = 2..
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magical cook
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| Posted: Thu Nov 29, 2007 7:43 am Post subject: |
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| Hi gabriel - got it - thanks! |
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