To find the percentage of any number, you multiply that number by the decimal version of your percent. 12% equals 0.12 as a decimal (you move the decimal to the right twice) or 12/100 as a fraction. So, we need to multiply 2600 by 0.12, or 12/100. I'm gonna assume you have a calculator or somethibg. if not, I can show you the long way in the comments. Anyway, if you multiply this, you get 312. However, that's just how much the population has increased--not the new population. we would need to add 312 to 2600 to get that value. in the end, we get 2912. Hope that helps!