Answer:
The simplest form of 28 elementary schools to 16 middle schools is 7 elementary schools to 4 middle schools written mathematically as,
in simplest form as 
Step-by-step explanation:
Given : 28 elementary schools to 16 middle schools
We have to write the ratio in simplest form.
28 elementary schools to 16 middle schools can be written in ratio form as 
We have write
in simplest form ,
Divide both numerator and denominator by 4, we have

Solving further we get,

Thus, the simplest form of 28 elementary schools to 16 middle schools is 7 elementary schools to 4 middle schools written mathematically as,
in simplest form as 