\begin{aligned}Payment=183000\\ \cos t=4200000\cdot 0,75\% =3150000=c\\ Payment=C\dfrac {\left( 1+i\right) ^{n}\cdot i}{\left( 1+i\right) ^{n}-1}\\ n=25years\times \dfrac {12manths}{1year}=300months\\ 18300=3150000\cdot \dfrac {\left( 1+i\right) ^{300}\cdot i}{\left( 1+i\right) ^{300}\cdot i}\\ i=0,0041\\ i is the monhly interest_{i}\\ i\times 12months=APR\\ APR=0,0123=1,23%\end{aligned}