Question

Use the Formula R = 6e12.77x, where x is the blood alcohol concentration and R, given in percent, is the risk of having a car accident.
Solve: What is blood alcohol concentration corresponds to a 25% risk of an accident?

Answer 1

I think with the next procedue I can help you a lot with it:

if
R = 50% 
x = Blood Alcohol Content (BAC) 
Then
50= 6 e^(12.77x) 
50/6 = e^(12.77x) 
ln(50/6) = 12.77x 
x = ln(50/6)/12.77 
x = 0.166 

I hope this can help you through