Difference between revisions of "2022 AMC 8 Problems/Problem 7"

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<math>\textbf{(A) } 0.6 \qquad \textbf{(B) } 10 \qquad \textbf{(C) } 1800 \qquad \textbf{(D) } 7200 \qquad \textbf{(E) } 36000</math>
 
<math>\textbf{(A) } 0.6 \qquad \textbf{(B) } 10 \qquad \textbf{(C) } 1800 \qquad \textbf{(D) } 7200 \qquad \textbf{(E) } 36000</math>
  
==Solution==
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==Solution 1==
  
 
Notice that the number of kilobits in this song is <math>4.2 \cdot 8000 = 8 \cdot 7 \cdot 6 \cdot 100.</math>
 
Notice that the number of kilobits in this song is <math>4.2 \cdot 8000 = 8 \cdot 7 \cdot 6 \cdot 100.</math>
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Finally, we divide  this number by <math>60</math> because this is the number of <i><b>seconds</b></i> to get the answer <math>\frac{600}{60}=\boxed{\textbf{(B) } 10}.</math>
 
Finally, we divide  this number by <math>60</math> because this is the number of <i><b>seconds</b></i> to get the answer <math>\frac{600}{60}=\boxed{\textbf{(B) } 10}.</math>
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~wamofan
 
~wamofan
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==Solution 2==
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We seek a value of <math>x</math> that makes the following equation true, since every other quantity equals <math>1</math>.
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<cmath>\frac{x\ \text{min}}{4.2\ \text{mb}} \cdot \frac{56\ \text{kb}}{1\ \text{sec}} \cdot \frac{1\ \text{mb}}{8000\ \text{kb}} \cdot \frac{60\ \text{sec}}{1\ \text{min}} = 1.</cmath>
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Solving yields <math>x=\boxed{\textbf{(B) } 10}</math>.
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-Benedict T (countmath1)
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 +
==Video Solution by Math-X (First understand the problem!!!)==
 +
https://youtu.be/oUEa7AjMF2A?si=ZRtIWQMPPOjOX9fB&t=822
 +
 +
~Math-X
 +
 +
==Video Solution (THINKING CREATIVELY!!!)==
 +
https://youtu.be/ZXMYmDPOypo
 +
 +
~Education, the Study of Everything
 +
 +
==Video Solution==
 +
https://www.youtube.com/watch?v=Ij9pAy6tQSg&t=475
 +
 +
~Interstigation
 +
 +
==Video Solution==
 +
https://youtu.be/1xspUFoKDnU?t=65
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 +
~STEMbreezy
 +
 +
==Video Solution==
 +
https://youtu.be/scSofI5OqkQ
 +
 +
~savannahsolver
 +
 +
==Video Solution==
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https://youtu.be/jmblFtkaKpc
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 +
~harungurcan
  
 
==See Also==  
 
==See Also==  
 
{{AMC8 box|year=2022|num-b=6|num-a=8}}
 
{{AMC8 box|year=2022|num-b=6|num-a=8}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Latest revision as of 13:38, 23 November 2023

Problem

When the World Wide Web first became popular in the $1990$s, download speeds reached a maximum of about $56$ kilobits per second. Approximately how many minutes would the download of a $4.2$-megabyte song have taken at that speed? (Note that there are $8000$ kilobits in a megabyte.)

$\textbf{(A) } 0.6 \qquad \textbf{(B) } 10 \qquad \textbf{(C) } 1800 \qquad \textbf{(D) } 7200 \qquad \textbf{(E) } 36000$

Solution 1

Notice that the number of kilobits in this song is $4.2 \cdot 8000 = 8 \cdot 7 \cdot 6 \cdot 100.$

We must divide this by $56$ in order to find out how many seconds this song would take to download: $\frac{\cancel{8}\cdot\cancel{7}\cdot6\cdot100}{\cancel{56}} = 600.$

Finally, we divide this number by $60$ because this is the number of seconds to get the answer $\frac{600}{60}=\boxed{\textbf{(B) } 10}.$

~wamofan

Solution 2

We seek a value of $x$ that makes the following equation true, since every other quantity equals $1$.

\[\frac{x\ \text{min}}{4.2\ \text{mb}} \cdot \frac{56\ \text{kb}}{1\ \text{sec}} \cdot \frac{1\ \text{mb}}{8000\ \text{kb}} \cdot \frac{60\ \text{sec}}{1\ \text{min}} = 1.\] Solving yields $x=\boxed{\textbf{(B) } 10}$.

-Benedict T (countmath1)

Video Solution by Math-X (First understand the problem!!!)

https://youtu.be/oUEa7AjMF2A?si=ZRtIWQMPPOjOX9fB&t=822

~Math-X

Video Solution (THINKING CREATIVELY!!!)

https://youtu.be/ZXMYmDPOypo

~Education, the Study of Everything

Video Solution

https://www.youtube.com/watch?v=Ij9pAy6tQSg&t=475

~Interstigation

Video Solution

https://youtu.be/1xspUFoKDnU?t=65

~STEMbreezy

Video Solution

https://youtu.be/scSofI5OqkQ

~savannahsolver

Video Solution

https://youtu.be/jmblFtkaKpc

~harungurcan

See Also

2022 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 6
Followed by
Problem 8
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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