Since this is simple interest the equation will be P*T*R=I T=time which is 1 year. P=money invested or borrowed (aka princable) which is 400$. R=Annual rate is 3% per year and I= Interest after the number of years (aka answer) Hope this helps :)
The answer is going to be 21 because 9+1=10, you then carry the 1 for 8 so it’s going to be 9+2 which equals to 11 now you carry the 1 to the 1 so it’ll be 2. Therefore it’s 21.0 or just cancel out the 0 and just leave it as 21.
