for this you're going to use the I=PRT formula! so i=interest, p=principal, r=rate, and t=time (in years). so basically here we are going to plug in the equation, I=(2700)*(0.016)*(0.5) and we get 21.60! I=PRT is a simple interest formula, which is used for the simple plug and chug equations like this. Just remember to convert months to years and move over your decimals!