Racism is literally written on the Brazilian DNA. The paternal lineage of average Brazilian is heavily European while the Maternal lineage is heavily African or Indigenous. You just gotta add 2 + 2 to understand what that means.
So do most white Brazilians have some African or Indigenous ancestry?
If you're looking at the official numbers the 2010 estimate was that 47.7% were White, 43.1% Mulatto and 7.6% Black. So a roughly even distribution between Whites and Blacks by the US defintion (and ignoring Indigenous ancestry for mixed race people). I assumed that meant an "average Brazilian" was a meaningless term (a bit like measuring the average racial background of a person in the Mississippi Delta).