private float getPercentFromLetter(char letter){
    if(letter == 'A'){
      return (100+75)/2;
    }
    else if(letter == 'B'){
      return (74+66)/2;
    }
    else if(letter == 'C'){
      return (65+57)/2;
    }
    else if(letter == 'D'){
      return (56+50)/2;
    }
    else {
      return (49+0)/2;
    }

  }