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- September 23rd 2011, 11:03 AM #1

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## How many different

There are 20 questions in the multichoice-exam and there are 4 answer alternatives on every question.

Only one alternative is always correct.

How many different answer papers is possible to form in which there are 70% of the answers correct?

Here is my solution ( I am not sure is this same formula needed here, but it might be right ) and that 70% would be * 0,7

(20 + 4 - 1)!

__________ * 0,7 =

20! * ( 4 - 1)!

- September 23rd 2011, 12:23 PM #2

- September 24th 2011, 12:10 AM #3

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- September 25th 2011, 11:22 AM #4

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## Re: How many different

I just want to make sure that I understood.

So this is 20 over 14

20

14

and should there be 4 *, I mean;

20 * 4

14

Because each question contains 4 alternatives. This probably is a big number.

It cannot be * 4! , but it might be * 4

- September 25th 2011, 11:29 AM #5

- September 25th 2011, 12:03 PM #6

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