if it's a 10% discount that means that it is 90% of the original price. I prefer to solve these types of questions by finding 1%, then multiplying it by 90.
1200 / 100 = 1% of original price = 12$
12$ x 90 = 1080$
if the tv cost $1,200 and had a 10% dicount you will pay $1,080
