Answer
$2043
Work Step by Step
We can calculate simple interest on a loan by using the formula $I=prt$ (where I is the interest, p is the principal, r is the rate of interest, and t is the amount of time - expressed in years).
$t=\frac{3}{2}$, because 18 months equals 1.5 years
$I=prt$
$I=1800\times.09\times\frac{3}{2}=243$ dollars
Finally, we can find the amount due by adding the interest to the original principal.
$1800+243=2043$ dollars
