Oh please, explain it to me then
In that area where those ballots were found, we'll say votes were about 2:1 in Biden's favor
That means that you have 2/3 probability of taking any one ballot and it being Biden
Now, you have to multiply 2/3 138,000 times to find the probability that out of a group of 138,000 ballots, all of them are for Biden
Now, why don't you go put 2/3 (or .66) to the power of 138,000 into a calculator and see what comes out (HINT: It's probably gonna be zero)