Answer
$a_n=750+150*n$, 1650 dollars/month
Work Step by Step
Base of 900 dollars
Increase of 150 per month
6 month training
$a_n=a_1+(n-1)*d$
$n=6$
$a_1=750$
$d=150$
$a_n=a_1+n*d$
$a_n=750+n*150$
$a_6=750+6*150$
$a_6=900+750$
$a_6=1650$
$a_n=750+150*n$, 1650 dollars/month