Your question is worded very well. But here is what I can make out of it.
I am assuming your interest is compound annually (once a year).
A = Final Amount $
P = Principal Amount $
R = Interest Rate %
N = # of times interest is compounded per time period
T = Time in Years
I = Amount if Interest Earned $
A = ?
P = ?
R = 5%
N = 1
T = 2
I = $1800
I solved for A and P.
A = $19,360.98
P = $17,560.98