If something is 20 percent off and its 30 dollars what is the discounted price

When eating out, record the total cost of your meal (before tip) and the tip that you left. determine the percent of the cost of the meal that you left as a tip.

The width of a rectangle is 20 units. can the perimeter p of the rectangle be 64 units when its length x is 11 units? no, because p = 2x + 2(20) no, because p ≠ 2x + 2(20) yes, because p ≠ 2x + 2(20) yes, because p = 2x + 2(20)

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)