We are given: One time bonus for hiring = $500.
The variable payment for earning commission = $250 per week.
Please see, in the given problem, when Katie was hired, they paied $500 as a hiring bonus.
So, at the time of hiring, there is not common added.
So, the initial value (amount) for the Katie is $500.
Every month the $250 is added as a commission amount.
Therefore, commoission amount is the rate of change for Katie's salary.
Rate of change : $250 and Initial value: $500.
