Question

Please assist me

Answer 1

@Neil15 @austinl @jim_thompson5910

Answer 2

\[\frac{p r}{12 \left(1-\left(\frac{r}{12}+1\right)^{-12 t}\right)}\text{/.}\, \{p\to 100000,r\to 0.0612,t\to 15\} \]
Mathematica calculates $850.354 per month