A store has a sale with 10% off every item. When you enter the store, you receive a coupon that states that you receive an additional 10% off. Is this equal to a 20% discount

It's not equal to 20% discount.

Step-by-step explanation:

Let's assume the cost of a good is $100. Since there's 10% off on every item, the cost of the good will be:

= $100 - (10% × $100)

= $100 - $10

= $90

Since the coupon states that one will receive an additional 10% off, therefore the amount that the person will pay will be:

= $90 - (10% × $90)

= $90 - (0.1 × $90)

= $90 - $9

= $81

If the same good is $100 and there's a 20% discount, the amount that'll be paid will be:

= $100 - (20% × $100)

= $100 - (0.2 × $100)

= $100 - $20

= $80

Therefore, it's not equal to 20% discount.

the two may have that, even a breakdown is probably offered