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Difference between revisions of "2016 AMC 8 Problems/Problem 5"

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==Solution==
 
==Solution==
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From the second bullet point, we know that the second digit must be 3. Because there is a remainder of 1 when it is divided by three, the multiple of 9 must end in a 2. We now look for this one:  
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From the second bullet point, we know that the second digit must be <math>3</math>. Because there is a remainder of <math>1</math> when it is divided by <math>9</math>, the multiple of <math>9</math> must end in a <math>2</math>. We now look for this one:  
  
 
<math>9(1)=9\\
 
<math>9(1)=9\\
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9(8)=72</math>
 
9(8)=72</math>
  
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The number <math>72+1=73</math> satisfies both conditions. We subtract the biggest multiple of 11 less than 73 to get the remainder. Thus, <math>73-11(6)=73-66=\boxed{\text{(E) }7}</math>.
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The number <math>72+1=73</math> satisfies both conditions. We subtract the biggest multiple of 11 less than 73 to get the remainder. Thus, <math>73-11(6)=73-66=\boxed{\textbf{(E) }7}</math>.
  
 
{{AMC8 box|year=2016|num-b=4|num-a=6}}
 
{{AMC8 box|year=2016|num-b=4|num-a=6}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 23:11, 27 November 2016

The number $N$ is a two-digit number.

• When $N$ is divided by $9$, the remainder is $1$.

• When $N$ is divided by $10$, the remainder is $3$.

What is the remainder when $N$ is divided by $11$?


$\textbf{(A) }0\qquad\textbf{(B) }2\qquad\textbf{(C) }4\qquad\textbf{(D) }5\qquad \textbf{(E) }7$

Solution

From the second bullet point, we know that the second digit must be $3$. Because there is a remainder of $1$ when it is divided by $9$, the multiple of $9$ must end in a $2$. We now look for this one:

$9(1)=9\\ 9(2)=18\\ 9(3)=27\\ 9(4)=36\\ 9(5)=45\\ 9(6)=54\\ 9(7)=63\\ 9(8)=72$

The number $72+1=73$ satisfies both conditions. We subtract the biggest multiple of 11 less than 73 to get the remainder. Thus, $73-11(6)=73-66=\boxed{\textbf{(E) }7}$.

2016 AMC 8 (Problems • Answer Key • Resources)
Preceded by
Problem 4 		Followed by
Problem 6
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 AJHSME/AMC 8 Problems and Solutions

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