How far can your grade in a class at school go down if you made a 30 on a daily grade that counts like 33%???

Question

i had an A

Answer 1

Lets say you averaged 90% on everything else.
It's this simple:
0.33(30) + 0.67(90) = 70.2

Here's a way of thinking of it that might make it more understandable:
Suppose your entire grade consisted of 100 quizzes. On 33 of them you got a 30 and on 67 of them you got a 90. How would you calculate that?
(33(30) + 67(90))/100 = 70.2