Difference between revisions of "2001 CEMC Gauss (Grade 8) Problems/Problem 7"

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<math>r + 15 = 25</math>
 
<math>r + 15 = 25</math>
  
<math>r = 10</math>
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<math>r = \boxed {\textbf {(B) } 10}</math>
  
 
~anabel.disher
 
~anabel.disher
 
{{CEMC box|year=2001|competition=Gauss (Grade 8)|num-b=6|num-a=8}}
 
{{CEMC box|year=2001|competition=Gauss (Grade 8)|num-b=6|num-a=8}}
 
{{CEMC box|year=2001|competition=Gauss (Grade 7)|num-b=8|num-a=10}}
 
{{CEMC box|year=2001|competition=Gauss (Grade 7)|num-b=8|num-a=10}}

Latest revision as of 17:28, 20 October 2025

The following problem is from both the 2001 CEMC Gauss (Grade 8) #7 and 2001 CEMC Gauss (Grade 7) #9, so both problems redirect to this page.

Problem

The bar graph shows the hair colours of the campers at Camp Gauss. The bar corresponding to redheads has been accidentally removed. If $50\%$ of the campers have brown hair, how many of the campers have red hair?


An image is supposed to go here. You can help us out by creating one and editing it in. Thanks.


$\text{ (A) }\ 5 \qquad\text{ (B) }\ 10 \qquad\text{ (C) }\ 25 \qquad\text{ (D) }\ 50 \qquad\text{ (E) }\ 60$

Solution 1

Let $r$ be the number of people with red hair. Since $50\%$ or half of the campers have brown hair, the total number of campers of the other hair colors must also be $25$. Thus, we have:

$5 + 10 + r = 25$

$r + 15 = 25$

$r = \boxed {\textbf {(B) } 10}$

~anabel.disher

2001 CEMC Gauss (Grade 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
CEMC Gauss (Grade 8)
2001 CEMC Gauss (Grade 7) (ProblemsAnswer KeyResources)
Preceded by
Problem 8
Followed by
Problem 10
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
CEMC Gauss (Grade 7)