combination of two sequences and other questions ;the 4 therms of an AS are 3;x;y;30 .find the values of x and y

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=