See attached picture for steps and answer:
So, 0.5^5 is 0.03125
multiply that by 125 and get your answer.
*3.90625* (4)
just saying, I got the 0.5^5 thing because 5 is the number of half-lives (x) and 0.5 is the rate of loss (or whatever its called).
If it were to gain, you would put 1.5
0.5 is the decimal equivalent to 1/2
