All the points are simply divided by 5 to get the answer. If it were -1/5, then the new points would be negative. (Or positive for the points initially negative).
28/50 thats what you have now you need to make it into 100 so you do 50x2=100 28x2=56 the answer 56/100 and the max is 100 percent so the answer is Nate Got 56 percent on the math homework