#### Answer

$\frac{28 people}{7 cars}=\frac{16 people}{4 cars}$

#### Work Step by Step

We are given that 28 people is to 7 cars as 16 people is to 4 cars. In order to write this as a proportion, we can write both relations as fractions.
28 people is to 7 cars can be written as $\frac{28 people}{7 cars}$
16 people is to 4 cars can be written as $\frac{16 people}{4 cars}$
Next, we can set both fractions equal to each other, which gives us a proportional relationship.
$\frac{28 people}{7 cars}=\frac{16 people}{4 cars}$
Since the units in the numerators and denominators are different, we do not simplify any further.