Answer: The percent change was 20%.
Explanation:
Given : Gabriel is the campaign manager for a candidate for governor.
Through a commissioned poll, he discovers that the candidate's approval rating has changed from 80 to 64 percentage.
I.e. Previous percentage = 80%
New percentage = 64%
Since 64< 80 , that means the percentage of approval has been decreased.
Decrease in percentage = (Previous percentage)- (New percentage)
= 80%-64%=16%
Percent change =


Hence, the percent change was 20%.