The formula for the intrest is,
[tex]I=\frac{P\cdot r\cdot t}{100}[/tex]Here, P is principal moner, r is rate percent and t is time in years.
Determine the intrest on $2000.
[tex]\begin{gathered} I=\frac{2000\cdot18\cdot\frac{1}{12}}{100} \\ =\frac{360}{12} \\ =30 \end{gathered}[/tex]So intrest is equal to $30.