You have two coupons for a store. Coupon 1 is for $10 dollars off. Coupon 2 is for 15% off. Coupon 2 is for 15% off. You can only use one coupon. Decide when you should use coupon 1 and when you should coupon 2. Please explain the coupons apply to a minimum purchase of $20

Purchases greater than 66.67 dollars should use coupon 2, while purchases between 20 dollars and 66.67 should use coupon 1.

Step-by-step explanation:

Coupon 1 must be used as long as those 10 dollars represent more money than 15% of coupon 2.

For example, if the purchase is the minimum of $ 20, 10 dollars represents half of the purchase, therefore in this case it is better to use coupon 1.

In this case, coupon 2 would only be a discount of 3 dollars (20 * 0.15).

So when from what value would it be better to use coupon 2, it would have to be calculated when it is worth more than 10 dollars.

10 = x * 0.15

x = 10 / 0.15

x = 66.67

That is to say that from the purchases greater than 66.67 dollars, coupon 2 would have a discount equivalent to 10 dollars or more.