If I get 1 dollar for the first A plus 2 dollars for the second A and 4 for the thirs A and so on doubling with each additional A, and I get 8 different grades How do I do this?

Answer 1

assuming they are all As, then you just need to know that

1+2+4+8+...+2^(n-1) = 2^n - 1

just use n=8