Using Excel for Calculations

Alcohol > Booze in the blood

Using percentages – Alcohol and equivalent “standard drinks”

These notes will help you with the activities in the Booze in blood CD. They show how to work out standard drinks using a calculator.

If you’re having a big night out, you need to keep track of the amount of alcohol you’ve had and the time you’ve been drinking. Factors like gender, weight and metabolism change how each person is affected by alcohol. They alter how quickly the alcohol is absorbed into the bloodstream and thus the individual’s blood alcohol concentration (BAC).

In Australia, alcoholic drinks are labeled to tell you the volume (how much liquid they contain) and the alcoholic strength (what percentage of the liquid is alcohol). In Australia, “a standard drink" contains 10 grams (about 12.5ml) of alcohol.

In order to drive a car legally in Australia, a person’s blood alcohol concentration (BAC) must be below 0.05. These guidelines are recommended to keep BAC below 0.05.

 Men can drink 2 standard drinks in the first hour and one standard drink each hour after that.  Women can have one standard drink per hour.  When drinking stops, most people get rid of about one standard drink per hour.

To predict whether someone is OK to drive, you need to

 calculate how much alcohol they’ve had in millilitres(mls) using the liquid volume and alcoholic percentage strength for each drink  change the mls of alcohol into an equivalent number of standard drinks  consider the time factor

Here is an example to show how it works.

Gill drinks 2 stubbies and a shot of bourbon over a 3-hour period. How much alcohol has she drunk altogether? What number of standard drinks is this? Is her blood alcohol concentration likely to be above or below 0.05?

To work this out we break the calculation up. Let’s deal first with the beer. How many A Stubby holds 375 ml of beer. The beer is 4.9 % alcohol in strength. mls of To work out how many milliliters of alcohol in one beer, we multiply the alcohol in volume (375ml) by the alcoholic strength (4.9%) the 375 x 4.9% = 18.4 stubbies? So in one stubby, there is 18.4ml of alcohol.

If Gill drinks more than one stubby, we multiply the amount of alcohol in one

1 Alcohol > Booze in the blood

stubby by the number of stubbies she’s had. She drank 2 stubbies, so she’s had 18.4 X 2 = 36.8 ml alcohol from the stubbies How many Now let’s find out how much alcohol in the shot of bourbon. mls of A shot glass holds around 30ml of liquid. Spirits like bourbon, vodka, whiskey alcohol in and rum are much stronger than beer and are around 40% alcohol. the bourbon shot? To work out how many milliliters of alcohol in one shot of bourbon, we multiply the volume (30ml) by the alcoholic strength (40%) 30 x 40% = 12 So in one shot of bourbon, there is 12ml of alcohol. What total To find out the total amount of alcohol Gill had, add up the mls of alcohol in amount of all the drinks she had. alcohol? 2 stubbies 36.8 ml 1 shot 12.0 ml

Total 48.8 ml Change mls of alcohol In Australia, the standard drink contains 10 gram or about 12.5ml of alcohol. into So to find how many standard drinks Gill had, we divide the total volume of equivalent alcohol (mls) by 12.5 standard 48.8 ÷ 12.5 = 3.9 drinks Gill has drunk the equivalent of 3.9 or, rounding off, 4 standard drinks.

OK to drive? Remember, to stay below a BAC of 0.05, men can drink 2 standard drinks in the first hour and one standard drink each hour after that. Women can have Let’s think one standard drink per hour. If they stop drinking, most people get rid of about BAC about one standard drink per hour. and time From the above calculations, Gill had about 4 standard drinks over 3 hours. Because Gill is female, the recommendation is one standard drink per hour. Gill would probably be over BAC 0.05 and thus unable to legally drive.

In contrast, a man who drank 4 standard drinks in 3 hours would probably be under 0.05 BAC and a legal driver.

2 Alcohol > Booze in the blood

Try this problem Jarred had 3 cans (375ml) of pre-mixed Rum and Coke (alcohol strength 5%) and 4 glasses(120 ml) of wine (alcohol strength 12%) over a 4 hour period. How much alcohol has he drunk altogether? What number of standard drinks is this? Is his blood alcohol concentration likely to be above or below 0.05?

Rum & coke 375 X 5% = 18.75

18.75 X 3 drinks = 56.25 ml Wine 120 X12% = 14.4

14.4 X 4 = 57.6 ml Total 56.25 + 57.6 = 113.85 So total alcohol is 113.85 ml Equiv st drinks 113.85 ÷ 12.5 = 9.1 So 9.1 standard drinks Time?? Jarred has drunk 9.1 standard drinks in 4 hours. Since Jarred is male, the recommendation is 2 +1+1+1 = 5 standard drinks over 4 hours to be below BAC 0.05. So Ben is probably well over BAC 0.05