Difference between revisions of "1984 AHSME Problems/Problem 6"

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==Solution==
 
==Solution==
From the given, we have <math> 3g=b </math> and <math> 9t=g </math>, or <math> t=\frac{g}{9} </math>. The sum of these, in terms of <math> g </math>, is <math> 3g+g+\frac{g}{9} </math>, or, with a common denominator, <math> \frac{37g}{9} </math>. We can see that this isn't one of the choices. So we write it in terms of <math> b </math>. We can see from the first equation that <math> g=\frac{b}{3} </math>, so substituting this into the expression yields <math> \frac{37b}{27}, \boxed{\text{B}} </math>.
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From the given, we have <math> 3g=b </math> and <math> 9t=g </math>, or <math> t=\frac{g}{9} </math>. The sum of these, in terms of <math> g </math>, is <math> 3g+g+\frac{g}{9} </math>, or, with a common [[denominator]], <math> \frac{37g}{9} </math>. We can see that this isn't one of the choices. So we write it in terms of <math> b </math>. We can see from the first [[equation]] that <math> g=\frac{b}{3} </math>, so substituting this into the expression yields <math> \frac{37b}{27}, \boxed{\text{B}} </math>.
  
 
==See Also==
 
==See Also==
 
{{AHSME box|year=1984|num-b=5|num-a=7}}
 
{{AHSME box|year=1984|num-b=5|num-a=7}}

Revision as of 20:00, 16 June 2011

Problem

In a certain school, there are $3$ times as many boys as girls and $9$ times as many girls as teachers. Using the letters $b, g, t$ to represent the number of boys, girls, and teachers, respectively, then the total number of boys, girls, and teachers can be represented by the expression

$\mathrm{(A) \ }31b \qquad \mathrm{(B) \ }\frac{37b}{27} \qquad \mathrm{(C) \ } 13g \qquad \mathrm{(D) \ }\frac{37g}{27} \qquad \mathrm{(E) \ } \frac{37t}{27}$

Solution

From the given, we have $3g=b$ and $9t=g$, or $t=\frac{g}{9}$. The sum of these, in terms of $g$, is $3g+g+\frac{g}{9}$, or, with a common denominator, $\frac{37g}{9}$. We can see that this isn't one of the choices. So we write it in terms of $b$. We can see from the first equation that $g=\frac{b}{3}$, so substituting this into the expression yields $\frac{37b}{27}, \boxed{\text{B}}$.

See Also

1984 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 5
Followed by
Problem 7
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