After applying the coupon, the large pizza price came down to $13.00 from $16.25
We need to figure out the percentage change of this.
The formula for percent change is:
The amount of change (decrease) is:
16.25 - 13.00 = 3.25
The original amount is:
16.25
We substitute these information into the formula and figure out our answer:

Thus, the decrease is 20%.
We can say that the coupon was 20% off coupon.