The answer is 460 because you have to subtract
I didn't know what you meant by phrase, so I put in a few:
X divided by 15
X over 15
There are some lollies they are to be divided between 15 children
Black lives matter , yes they do
So, since it is continuously, we need to think of PERT

So, we just plug our numbers in to solve for T

It will take 15.479 years