I really need help with this one

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 tt of tokens james has is a function of gg, the number of games he plays

A50% increase followed by 33 1/2% decrease

Me d is also an option but i couldn't get it in the picture