The answer to your question is
BAC is used to determine how many drinks someone has consumed.
![\bf Explanation :](https://img.qammunity.org/2019/formulas/health/middle-school/6kvcsgoan8w0fr9mcb8egi015bpog5yw67.png)
BAC is used to determine the level of intoxication. It does this by measuring the weight of ethanol in a certain amount of blood. BAC is used to determine the amount of alcohol in blood,
not how many drinks someones consumed.
I hope this helps!