Difference between revisions of "2007 Cyprus MO/Lyceum/Problem 5"

 
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==Problem==
 
==Problem==
If the remainder of the division of <math>a</math> with <math>35</math> is <math>23</math>, then the remainder of the division of <math>a</math> with <math>7</math> is
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If the [[modular arithmetic|remainder]] of the division of <math>a</math> with <math>35</math> is <math>23</math>, then the remainder of the division of <math>a</math> with <math>7</math> is
  
 
<math> \mathrm{(A) \ } 1\qquad \mathrm{(B) \ } 2\qquad \mathrm{(C) \ } 3\qquad \mathrm{(D) \ } 4\qquad \mathrm{(E) \ } 5</math>
 
<math> \mathrm{(A) \ } 1\qquad \mathrm{(B) \ } 2\qquad \mathrm{(C) \ } 3\qquad \mathrm{(D) \ } 4\qquad \mathrm{(E) \ } 5</math>
  
 
==Solution==
 
==Solution==
{{solution}}
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<math>\displaystyle  a \equiv 23 \pmod{35}</math> and <math>\displaystyle 7 | 35</math>, so <math>\displaystyle a \equiv 23 \equiv 2 \pmod{7} \Longrightarrow \mathrm{B}</math>.
  
 
==See also==
 
==See also==
*[[2007 Cyprus MO/Lyceum/Problems]]
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{{CYMO box|year=2007|l=Lyceum|num-b=4|num-a=6}}
  
*[[2007 Cyprus MO/Lyceum/Problem 4|Previous Problem]]
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[[Category:Introductory Algebra Problems]]
 
 
*[[2007 Cyprus MO/Lyceum/Problem 6|Next Problem]]
 

Latest revision as of 15:22, 6 May 2007

Problem

If the remainder of the division of $a$ with $35$ is $23$, then the remainder of the division of $a$ with $7$ is

$\mathrm{(A) \ } 1\qquad \mathrm{(B) \ } 2\qquad \mathrm{(C) \ } 3\qquad \mathrm{(D) \ } 4\qquad \mathrm{(E) \ } 5$

Solution

$\displaystyle  a \equiv 23 \pmod{35}$ and $\displaystyle 7 | 35$, so $\displaystyle a \equiv 23 \equiv 2 \pmod{7} \Longrightarrow \mathrm{B}$.

See also

2007 Cyprus MO, Lyceum (Problems)
Preceded by
Problem 4
Followed by
Problem 6
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