Answer:
Option 3rd is correct
29 alternative schools are in the county
Explanation:
Let x be the alternative schools are in the county.
As per the statement:
In a certain county, the number of charter schools is 6 less than twice the number of alternative schools.
⇒Number of charter school = 2x - 6
It is also given that we know that there are 52 charter schools in the county.
⇒Number of charter school =52
then;

Add 6 to both sides we have;

Divide both sides by 2 we have;
⇒x = 29
Therefore, 29 alternative schools are in the county