Respuesta :
The contestants total points is 150. My reasoning is that 100 + -250 = - 350, and -350 + 500 = 150 points.
-100 the end of first round;
-100-250= -350 at the end of second round;
-350+500= 150 points at the end of third round.
-100-250= -350 at the end of second round;
-350+500= 150 points at the end of third round.