Question 7716
This is kind of difficult because we don't know the length of time.

Yet, to get the interest rate you would

{{{$45/$1500=x/100}}}
{{{4500=1500x}}}
{{{3%=x}}}

{{{$2000x0.3=$6.00}}}

To get the interest over a period of time you would use 
I=PRT or Interest=principle x time x rate.  We don't have the time period. 

I hope that helps you.