Answer:
19%
Explanation:
The first discount is the 10% off.
An item costs 100% of its original price. By discounting 10%, the discounted price is now only 90% of the original price.
The price is now 90% of the original price. This is before the coupon is used.
Now we use the coupon. The coupon is 10% off of the discounted price.
That means now you will pay 90% of the discounted price.
The discounted price is 90% of the original price, so after the 10% coupon, you pay 90% of 90% of the original price.
90% * 90% = 0.90 * 0.90 = 0.81 = 81%
After the discount and the coupon, you pay 81% of the original price.
The price before the discount and the coupon was 100% of the original price.
Now the price is 81% of the original price.
100% - 81% = 19%
The final price has a total percent of discount of 19%.