I don’t understand how to solve it

Answer:
x= $878.85
Step-by-step explanation:
1349.99=1350
1350=100% you cross multiply and then divide by 100 you get x = 540
x =40%
504 is how much can be off the original price, 1350-504=810
You would pay 810 dollars if the coupon was 40% off. Now we gotta find how much is the tax rate.
810=100% do the cross multiply and then divide by a 100, you get x=68.85
x =8.5
Then you have to add your tax rate to the price that you are paying, 810+68.85=$878.85.
Hope this helps you!