2001 CEMC Gauss (Grade 8) Problems/Problem 7

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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?


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

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)