Find the exact area of the trapezoid

How is the number of vertices for a prism related to the name of the prism

Can some one me with these questions

James is playing his favorite game at the arcade. after playing the game 3 times, he has 8 tokens remaining. he initially had 20 tokens, and the game costs the same number of tokens each time. the number t of tokens james has is a function of g, the number of games he plays. write the function’s formula? t=