A recursive formula represent the nth terms of a sequence in terms of it's previous (n-1)th term and it include first term.
Let's assume,
= First term,
= nth term,
= Previous term of nth term or (n-1) the term.
According to the problem,
Jobie starts with $325 in her piggy bank. Each month she adds $10.
Which means first term: 
Since he is adding $10 each month. So, this month if he will have
then in the next month he will have
.
So, the recursive formula will be ,
