Major - 55%, Current Grade
Minor - 35%, Current Grade
Practice - 10%, Current Grade

Total grade - 100%, Current Grade
Major - 55%, Current Grade
Minor - 35%, Current Grade
Prac. - 10%, Current Grade
0.55(Current Grade) + 0.35(Current Grade) + 0.10(Current Grade)
= Current Grade * 0.55 + Current Grade * 0.35 + Current Grade * 0.10
= Current Grade