Question

PLZ PLZ HELP ME I don't understand it

Answer 1

Is it because the second discount will be determined by the first discounted price, $405, not $450.

Answer 2

The first time you see the TV discounted as 10%, the cost of the TV is 90% of $450 which is $405. The second time you see the TV discounted, it is discounted from the discounted price, which was $405. 90% of 405 is 364.5, so the newest sales price is $364.50.

If you discounted 20% from the original price of the TV, you would get a completely different answer. 80% of $450 is $360.