The population of ketchum high school has been decreasing by 5% per year. if it's population is currently 2,600 students, which of te following is closer to its population two years from now?

I think its 206 because you'll have to change  5% into a decimal and you'll
get 0.05 because you move the decimal place to the left 2 times. Then multiply
2,600 to 0.05 to get what the population decreasing for a year, (130) then multiply is by 2 (for 2 years) and you'll get
260 students. 
-Have fun in math :/

All you have to do is add them up! 
30cm2 is your answer!