I don’t understand that’s not a question?
The reason fractions need a common denominator before adding or subtracting is so that the numbers of pieces you are adding/subtracting are all the same size. Note that the numerator of a fraction just tells you how many pieces you have of that size.
Answer:
60 miles
Step-by-step explanation:
20 miles times 3

Both equations are equivalent, so there are infinitely many solutions.