Let's start with part A, which you tried. I suspect you did the correct work, but misinterpreted the answer and then mishandled that.
The function gives a percentage of animals, not in the sense that it gives a decimal you can write as a percentage (e.g. 0.11 could be written as 11%), but in the sense that if the answer were 0.11%, the function would give the number 0.11. (I know this because for very large values of t, V(t) will approach 100.)
The value of V(13) is not 0.11! Give that another try.
Then try part B, showing whatever work you are able to do. You should be writing an equation that you will solve for t; but any part of the work will give us an idea of what help you need.