You are going to spend $47.50 to play games at the fair. each game costs $0.50 per play. which of these equations best shows how much money you have left as you play the games?
a : money left = -50 • games played + 47.50
b : money left = -0.50 • games played + 47.50
c : money left = 0.50 • games played + 47.50
d : money left = 47.50 • games played + 0.50