Answer: 25
Step-by-step explanation:
Given
The student earned 80% on a math test
The student answered 20 questions
Suppose x is the total no of questions
So, we can write
[tex]\Rightarrow \dfrac{20}{x}\times 100=80\%\\\Rightarrow \dfrac{20}{x}=0.8\\\\\Rightarrow \dfrac{20}{0.8}=x\\\\\Rightarrow x=25[/tex]
So, there are 25 questions in total
