Learning Resources

Investigation 7: Investing in Toys

Test yourself

Using the equation we have:

The amount of alcohol at the beginning of the test was . This is the initial amount, thus a = 100.  Since we are talking about when half remains, the common ratio is ½ and thus b = ½ . This ratio of half occurs every 3 hours, thus c = 3 . The equation is therefore:

Substituting x = 8 into this equation gives:

After 8 hours,  approximately of alcohol remain in the bloodstream.