14 points to who solves it

An appropriate solution for r is ...
[tex]A=P(1+rt)\\\\A=P+Prt \qquad\text{correctly use the distributive property}\\\\A-P=Prt \qquad\text{subtract P}\\\\\dfrac{A-P}{Pt}=r \qquad\text{divide by the coefficient of r}\\\\r=\dfrac{A-P}{Pt} \qquad\text{write with r on the left}[/tex]
The denominator factor can be changed to Pt to correct the error made in the use of the distributive property.