Question 457268: Page 548 # 1
Police use blood alcohol content (ABC) to measure the percent concentration of alcohol in a person’s bloodstream. In most states, a BAC of 0.08 percent means person is not allowed to drive. Each hour after drinking, a person’s ABC may decrease by 15%. If a person has BAC of 0.18, how many hours will he need to wait he can legally drive?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In most states, a BAC of 0.08 percent means person is not allowed to drive. Each hour after drinking, a person’s ABC may decrease by 15%. If a person has BAC of 0.18, how many hours will he need to wait he can legally drive?
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Start 0.18
After 1 hr: 0.18-0.15*0.18 = (1-0.15)0.18 = 0.85*0.18
After 2 hr: 0.85^2*0.18
etc.
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Solve:
0.85^n(0.18) < 0.08
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0.85^n < 0.08/0.18 = 0.4444
n > log(0.4444)/log(0.85)
n > 4.9899
n >= 5 hrs.
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Cheers,
Stan H.
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