So u turn the percent into a decimal. 0.10 Now multiply 1200 * 0.10 1200*0.10= 120 ( 120 is the amount that is gonna increase) So if it says 5 years, than your gonna multiply 120 * 5 120*5 =600 So your gonna add 600 to 1200. So in five years your gonna be making 1,800. An easier way would be to use prt Principle * rate * time 1200 * 0.10* 5 = 600 So now you just add 600 to 1200 = 1800