There is an error in the formula used. The correct expression is $$A(0)(1+0.06)^{4.5}=20000$$ $$A(0)=\frac{20000}{1.06^{4.5}}=15386.99$$
There is an error in the formula used. The correct expression is $$A(0)(1+0.06)^{4.5}=20000$$ $$A(0)=\frac{20000}{1.06^{4.5}}=15386.99$$