Find the mass and center of mass of the s solid bounded by the paraboloid z = 6x2 + 6y2 and the plane z = a (a > 0) if s has constant density k. use cylindrical coordinates.

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

Can you me with this question? i'll reward *30 points i just need with this one question so that i could solve the others. * edit: i originally set up the question to reward 30 points, but for some reason i can only reward 15. if you don't get 30, then i'm sorry. i'm still kind of new to this site

Huong is organizing paperback and hardback books for her club's used book sale. the number of paperbacks is 12 less than three times the number of hardbacks. huong had 162 paperbacks. how many hardback books were there?