What is the percent increase from 0 to 19?
Your solution to this question needs a lot of forethought. Se what I have written in the 'Explanation'.
There is a trap in this question!
What you normally have is
The problem is that the original is 0 and mathematically you are not allowed to have 0 as a denominator. This condition is called 'undefined'
Suppose you had instead:
This would give:
You now have a permitted value but again there is a problem as in
same as tony's, see explanation
just wanted to add that when you increase something by multiplication (which is implied in the original question) you need numbers bigger than zero. increasing 1 five times gives you 5, however anything multiplied by zero is always zero so starting at zero and increasing it will never give you 19.