Answer
300
Work Step by Step
Solving Variation Problems (see p. 424)
1. $\ \ $Write an equation that models the given English statement.
2. $\ \ $Substitute the given pair of values into the equation in step 1 and find the value of k, the constant of variation.
3. $\ \ $Substitute the value of k into the equation in step 1.
4. $\ \ $Use the equation from step 3 to answer the problem's question.
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1.
$C$ varies directly as $A$ or $C$ is directly proportional to $A$.
$C=kA$
$C$ varies directly as $T$ or $C$ is directly proportional to $T$.
$C=kT$
Combined: $C=kAT$
2.
$175=k(2100)(4) $
$175=8400k \qquad /\div 8400$
$k=\displaystyle \frac{175}{8400}=\frac{1}{48}$
3.
$y=\displaystyle \frac{1}{48}xz$
4.
$y=\displaystyle \frac{1}{48}(2400)(6) =\frac{14400}{48}=300$
