"Ace" wrote

Now, let's say that in 19 of those 20 states only one person votes per
state and that vote is cast for candidate A, and in one of those 20
states 20 people vote for candidate B.

In the popular vote candidate A receives 19 votes and candidate B
receives 20 votes.

Which candidate is elected, and by what majority?

Candidate A will receive 19 electoral votes, and Candidate B will receive
1 electoral vote. Candidate A is the winner 19:1