Let <em>n </em>represent the date and <em>f(n)</em> represent the money on a specific day.
We see that the pattern is every day, we add $0.50 into our little piggy bank. So on day 1, we get $0.50 and on day 2, we get $1.00. We can see it is a linear function and since in is increasing by $0.50, our slope <em>m </em>is $0.50.