Marco's bought a bookcase that was 25% of the regular price. he also bought a package of pens for $3 he paid a total of $60 for the bookcase and pens, not including tax. what was the regular price of the book case?

With number 11 ( show how you got the answer)

Mason and christian go to the movie theater and purchase refreshments for their friends. mason spends a total of $45.75 on 3 bags of popcorn and 6 drinks. christian spends a total of $71.50 on 6 bags of popcorn and 4 drinks. write a system of equations that can be used to find the price of one bag of popcorn and the price of one drink. using these equations, determine and state the price of a drink, to the nearest cent.

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.