Difference between revisions of "2023 AMC 8 Problems/Problem 13"

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==Problem==
 
==Problem==
  
Along the route of a bicycle race, 7 water stations are evenly spaced between the start and finish lines,
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Along the route of a bicycle race, <math>7</math> water stations are evenly spaced between the start and finish lines,
as shown in the figure below. There are also 2 repair stations evenly spaced between the start and
+
as shown in the figure below. There are also <math>2</math> repair stations evenly spaced between the start and
finish lines. The 3rd water station is located 2 miles after the 1st repair station. How long is the race
+
finish lines. The <math>3</math>rd water station is located <math>2</math> miles after the 1st repair station. How long is the race
 
in miles?
 
in miles?
 
+
[[File:2023 AMC 8-13.png|center|500px]]
[[File:2023 AMC 8-13.png|thumb|center|300px]]
 
 
 
 
<math>\textbf{(A)}\ 8 \qquad \textbf{(B)}\ 16 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 48 \qquad \textbf{(E)}\ 96</math>
 
<math>\textbf{(A)}\ 8 \qquad \textbf{(B)}\ 16 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 48 \qquad \textbf{(E)}\ 96</math>
  
 
+
==Solution==
==Solution 1==
 
  
 
Knowing that there are <math>7</math> equally spaced water stations they are each located <math>\frac{d}{8}</math>, <math>\frac{2d}{8}</math>,… <math>\frac{7d}{8}</math> of the way from the start. Using the same logic for the <math>3</math> station we have <math>\frac{d}{3}</math> and <math>\frac{2d}{3}</math> for the repair stations. It is given that the 3rd water is <math>2</math> miles ahead of the <math>1</math>st repair station. So setting an equation we have <math>\frac{3d}{8} = \frac{d}{3} + 2</math> getting common denominators <math>\frac{9d}{24} = \frac{8d}{24} + 2</math> so then we have <math>d =  \boxed{\text{(D)}~48}</math> from this.
 
Knowing that there are <math>7</math> equally spaced water stations they are each located <math>\frac{d}{8}</math>, <math>\frac{2d}{8}</math>,… <math>\frac{7d}{8}</math> of the way from the start. Using the same logic for the <math>3</math> station we have <math>\frac{d}{3}</math> and <math>\frac{2d}{3}</math> for the repair stations. It is given that the 3rd water is <math>2</math> miles ahead of the <math>1</math>st repair station. So setting an equation we have <math>\frac{3d}{8} = \frac{d}{3} + 2</math> getting common denominators <math>\frac{9d}{24} = \frac{8d}{24} + 2</math> so then we have <math>d =  \boxed{\text{(D)}~48}</math> from this.
  
 
~apex304, SohumUttamchandani, wuwang2002, TaeKim, Cxrupptedpat
 
~apex304, SohumUttamchandani, wuwang2002, TaeKim, Cxrupptedpat
 
==Solution 2 (answer choices)==
 
 
Test all the answer choices, and find that the answer is <math>\boxed{\text{(D)}~48}</math>
 
 
-claregu
 
 
  
 
==Video Solution (Animated)==
 
==Video Solution (Animated)==

Revision as of 15:20, 25 January 2023

Problem

Along the route of a bicycle race, $7$ water stations are evenly spaced between the start and finish lines, as shown in the figure below. There are also $2$ repair stations evenly spaced between the start and finish lines. The $3$rd water station is located $2$ miles after the 1st repair station. How long is the race in miles?

2023 AMC 8-13.png

$\textbf{(A)}\ 8 \qquad \textbf{(B)}\ 16 \qquad \textbf{(C)}\ 24 \qquad \textbf{(D)}\ 48 \qquad \textbf{(E)}\ 96$

Solution

Knowing that there are $7$ equally spaced water stations they are each located $\frac{d}{8}$, $\frac{2d}{8}$,… $\frac{7d}{8}$ of the way from the start. Using the same logic for the $3$ station we have $\frac{d}{3}$ and $\frac{2d}{3}$ for the repair stations. It is given that the 3rd water is $2$ miles ahead of the $1$st repair station. So setting an equation we have $\frac{3d}{8} = \frac{d}{3} + 2$ getting common denominators $\frac{9d}{24} = \frac{8d}{24} + 2$ so then we have $d =  \boxed{\text{(D)}~48}$ from this.

~apex304, SohumUttamchandani, wuwang2002, TaeKim, Cxrupptedpat

Video Solution (Animated)

https://youtu.be/NivfOThj1No

~Star League (https://starleague.us)

Video Solution by Magic Square

https://youtu.be/-N46BeEKaCQ?t=4439

See Also

2023 AMC 8 (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 AJHSME/AMC 8 Problems and Solutions

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