Answer:
44.7 mg
Explanation:
The equation for exponential decay can be written in the form ...
y = a·b^(t/p)
where 'a' is the initial value, 'b' is the decay factor, 'p' is the period over which the decay factor is applicable, and t is time in the same units as p.
Setup
Using the above equation, we have ...
a = initial value = 110 mg
b = decay factor = 55/110 = 1/2 over time period p=20 hours
Then the equation is ...
y = 110·(1/2)^(t/20) . . . . amount remaining after t hours
Solution
We want the amount remaining after 26 hours. That will be ...
y = 110·(1/2)^(26/20) ≈ 44.67
About 44.7 milligrams will remain after 26 hours.