Applications of Proportions

EXAMPLE 6.40

Write each sentence as a proportion:

(a) $3$ is to $7$ as $15$ is to $35$.

(b) $5$ hits in $8$ at bats is the same as $30$ hits in $48$ at-bats.

(c) $\$ 1.50$ for 6 ounces is equivalent to $\$ 2.25$ for $9$ ounces.

EXAMPLE 6.41

Determine whether each equation is a proportion:

(a) $\dfrac{4}{9}=\dfrac{12}{28}$

(b) $\dfrac{17.5}{37.5}=\dfrac{7}{15}$

EXAMPLE 6.42

Solve: $\dfrac{x}{63}=\dfrac{4}{7}$.

EXAMPLE 6.43

Solve: $\dfrac{144}{a}=\dfrac{9}{4}$.

EXAMPLE 6.44

Solve: $\dfrac{52}{91}=\dfrac{-4}{y}$.