I can't figure the following questions out:

1) For all real numbers v, the operation V* is defined by the equation V*=V-V/3. If (V*)*=8, the v=

A)15

B)18

C)21

D)24

E)27

The answer happens to be B)18

2) A rectangular tabletop consists of a pice of laminated wood bordered by a thin metal strip along its four edges. The surface area of the tabletop is x square feet, and the total length of the strip before it was attached was x feet. If the tabletop is 3 feet wide, what is its approximate length, in feet?

A)12

B)10

C)9

D)8

E)6

The answer is B)10

Can someone explain these answers to me.

Thanks!