Least number problem

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Least number problem

by jfranco23 » Tue Feb 24, 2009 11:58 am
A researcher plans to identify each participant in a certain medical experiment with a code consisting of either a single letter or a pair of distinct letters written in alphabetic order. What is the last number of letters that can be used if there are 12 participants, and each participant is to receive a different code?

A. 4
B. 5
C. 6
D. 7
E. 8
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Re: Least number problem

by x2suresh » Tue Feb 24, 2009 12:00 pm
jfranco23 wrote:A researcher plans to identify each participant in a certain medical experiment with a code consisting of either a single letter or a pair of distinct letters written in alphabetic order. What is the last number of letters that can be used if there are 12 participants, and each participant is to receive a different code?

A. 4
B. 5
C. 6
D. 7
E. 8
4C1 +4C2 = 10
5C1+5C2 = 5+10 =15

B