A head to head comparison of the Tennessee 2020 Primary gives us an idea of the break down of the voters.
Donald Trump got 44% (384k) of the vote to beat Joe Bider (215k votes) by 25% and Bernie Sanders (129k votes) by 15%.
In the Primary, Trump won 91 counties in the 3-way match up. Joe Biden trailed behind Trump winning 4 counties. Sanders won no counties in Tennessee Primary.
These 10 counties play an important role in these primary elections. Winning among the top 10 counties is the best way to gain the most voters. Shelby and Davidson counties contain the highest number of voters. As described below, Joe Biden had a large voter turnout from these top two counties, which provided his many votes, though not enough votes to beat Donald Trump.
Bernie Sanders vs Joe Biden
Joe Biden vs Donald Trump
Donald Trump vs Joe Biden
In a head to head match up on just the total number of votes, Joe Biden (62%) beats Bernie Sanders (38%). Donald Trump (75%) beats Bernie Sanders (25%). Donald Trump (64%) beats Joe Biden (36%).
Donald Trump won 91 counties, securing him the victory in the state of Tennessee in the 2020 Primary elections despite the fact that his top 10 counties did not have as many votes as Joe Biden top 10 counties. Donald Trump won because he won so many counties. Joe Biden only won 4 counties in the state of Tennessee.