Sara is shopping at a store that offers cash back on on every spent.

Let

.

Where represents amount of money spent by sara.

(a).

represents number of times spent.

represents the cash back bonus.

The cash back bonus is found after calculating the number of times was spent. So, the cash back bonus is represented by .

(b).

Cash Back Bonus if sara spent at the store.

The cash back bonus is .

(a). The cash back bonus is represented by .

(b). The cash back bonus is .