Difference between revisions of "2010 AMC 12B Problems/Problem 4"

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== Solution ==
 
== Solution ==
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31%7 = 3 so the week cannot start with Saturday, Sunday, Tuesday or Wednesday as that would result in an unequal number of Mondays and Wednesdays. Therefore Monday, Thursday and Friday are valid so the answer is (B).
  
 
== See also ==
 
== See also ==
 
{{AMC12 box|year=2010|num-b=12|num-a=14|ab=B}}
 
{{AMC12 box|year=2010|num-b=12|num-a=14|ab=B}}

Revision as of 15:59, 17 January 2011

Problem 4

A month with $31$ days has the same number of Mondays and Wednesdays.How many of the seven days of the week could be the first day of this month?

$\textbf{(A)}\ 2 \qquad \textbf{(B)}\ 3 \qquad \textbf{(C)}\ 4 \qquad \textbf{(D)}\ 5 \qquad \textbf{(E)}\ 6$

Solution

31%7 = 3 so the week cannot start with Saturday, Sunday, Tuesday or Wednesday as that would result in an unequal number of Mondays and Wednesdays. Therefore Monday, Thursday and Friday are valid so the answer is (B).

See also

2010 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 12
Followed by
Problem 14
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 12 Problems and Solutions