Answer:
r = 3.5 * .5^(t/65); around 117.5 days
Step-by-step explanation:
r = remaining substance
t = time in days
The half life is 65 day, meaning the .5 must be put to a power of t/65.
The initial substance was 3.5, which we must substitute in.
After using logarithms to solve our new equation, we are left with t=(about)117.5 days for there to be less than 1 gram of substance remaining.
The answer is A!!
