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

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==Problem==
 
==Problem==
In a certain school, there are <math> 3 </math> times as many boys as girls and <math> 9 </math> times as many girls as teachers. Using the letters <math> b, g, t </math> 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
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In a certain school, there are <math> 3 </math> times as many boys as girls and <math> 9 </math> times as many girls as teachers. Using the letters <math> b, g, t </math> 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]]
  
 
<math> \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} </math>
 
<math> \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} </math>

Revision as of 19:59, 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
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 26 27 28 29 30
All AHSME Problems and Solutions