He has 900 coins.
There are multiple ways to get this answer, but the easiest and most logical (in my opinion) way is this:
A percent is out of 100.
We have 2 percent in this problem. So, how would you get 2 to become 100?
Multiply 2 by 50 to get 100.
So, we do the same for the other number.
18 multiplied by 50 is 900.
If you have any questions then feel free to ask.
