On a quiz you answered 20 questions correctly out of 28. what percent did you answer correctly rounded to the nearest percent? show work

Can someone me and do the problem plz so i can understand it more better

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

Handsome jack is buying a pony made of diamonds. the price of the pony is p dollars, and jack also has to pay a 25% diamond pony tax. which of the following expressions could represent how much jack pays in total for the pony?