You drink a beverage with 120 mg of caffeine. each hour, the caffeine in your system decreases by about 12%. how many milligrams of caffeine will be in your system after 8 hours? round to two decimal places? can someone show me how to work this problem out?

 43.16 mg

Step-by-step explanation:

After each hour, the amount remaining is 100% - 12% = 0.88 times the amount present at the beginning of the hour. Then after 8 hours, the amount remaining will be the initial amount multiplied by 0.88 eight times, or ...

  (120 mg)·(0.88^8) ≈ 43.1561 mg ≈ 43.16 mg

Of course, an exponent is used to signify repeated multiplication. You can actually do the multiplication if you like, but most scientific and graphing calculators handle exponentiation easily.

18

step-by-step explanation:

ik this stuph and i am smart donkey

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)