Answer: a)

b)85%
c)0.85
Explanation:
Given : Justine answered 68 questions correctly on an 80 questions test .
Thus, Total answers = 80
Correct answers= 68
In fraction,

On dividing both numerator and denominator by 4, we get fraction in simplest form

To convert in decimal divide 17 by 20 , we get 0.85
To convert in percent multiply 100 to the decimal, we get 85%