The division expression that shows what fraction of time Sebastian walked the dog today is 4/5.
A fraction is a quantity that is not a whole number. A fraction consists of a numerator and a denominator. The numerator is the number above. While the denominator is the number below. An example of a fraction is 1/2. 1 is the numerator while 2 is the denominator.
Fraction of the time used to walk the dog = minutes the dog was walked / total time used to walk the dog
= 20 / 25
Expressed in its simplest form, it becomes 4 / 5.
To learn more about the division of fractions, please check: https://brainly.com/question/25779356