Difference between revisions of "2004 AMC 12B Problems/Problem 8"

 
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== Problem ==
 
== Problem ==
A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the row above it. If the display contains 100 cans, how many rows does it contain?
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A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the row above it. If the display contains <math>100</math> cans, how many rows does it contain?
  
<math>(\mathrm {A}) 5 \qquad (\mathrm {B}) 8 \qquad (\mathrm {C}) 9 \qquad (\mathrm {D}) 10 \qquad (\mathrm {E}) 11</math>
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<math>\mathrm{(A)\ }5\qquad\mathrm{(B)\ }8\qquad\mathrm{(C)\ }9\qquad\mathrm{(D)\ }10\qquad\mathrm{(E)\ }11</math>
  
 
== Solution ==
 
== Solution ==
  
The sum of the first <math>n</math> odd numbers is <math>n^2</math>. As in our case <math>n^2=100</math>, we have <math>n=\boxed{10}\Longrightarrow\mathrm{(D)}</math>.
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The sum of the first <math>n</math> odd numbers is <math>n^2</math>. As in our case <math>n^2=100</math>, we have <math>n=\boxed{\mathrm{(D)\ }10}</math>.
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== Video Solution 1==
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https://youtu.be/2Yqy5G8G1IU
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~Education, the Study of Everything
  
 
== See Also ==
 
== See Also ==
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{{AMC12 box|year=2004|ab=B|num-b=7|num-a=9}}
 
{{AMC12 box|year=2004|ab=B|num-b=7|num-a=9}}
 
{{AMC10 box|year=2004|ab=B|num-b=9|num-a=11}}
 
{{AMC10 box|year=2004|ab=B|num-b=9|num-a=11}}
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{{MAA Notice}}

Latest revision as of 18:24, 22 October 2022

The following problem is from both the 2004 AMC 12B #8 and 2004 AMC 10B #10, so both problems redirect to this page.

Problem

A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the row above it. If the display contains $100$ cans, how many rows does it contain?

$\mathrm{(A)\ }5\qquad\mathrm{(B)\ }8\qquad\mathrm{(C)\ }9\qquad\mathrm{(D)\ }10\qquad\mathrm{(E)\ }11$

Solution

The sum of the first $n$ odd numbers is $n^2$. As in our case $n^2=100$, we have $n=\boxed{\mathrm{(D)\ }10}$.

Video Solution 1

https://youtu.be/2Yqy5G8G1IU

~Education, the Study of Everything

See Also

2004 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 7
Followed by
Problem 9
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
2004 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 9
Followed by
Problem 11
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 10 Problems and Solutions

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