The answer is B, 5/6, because when you multiply 4 by 5 it is 20, and when you multiply 5 by 6, you get 30, so 20/30. And, 20/30=2/3. I hope I answered your question!
Answer:
the maximum concentration of the antibiotic during the first 12 hours is 1.185
at t= 2 hours.
Step-by-step explanation:
We are given the following information:
After an antibiotic tablet is taken, the concentration of the antibiotic in the bloodstream is modeled by the function where the time t is measured in hours and C is measured in 

Thus, we are given the time interval [0,12] for t.
- We can apply the first derivative test, to know the absolute maximum value because we have a closed interval for t.
- The first derivative test focusing on a particular point. If the function switches or changes from increasing to decreasing at the point, then the function will achieve a highest value at that point.
First, we differentiate C(t) with respect to t, to get,

Equating the first derivative to zero, we get,

Solving, we get,

At t = 0

At t = 2

At t = 12

Thus, the maximum concentration of the antibiotic during the first 12 hours is 1.185
at t= 2 hours.
Distribution property. You would distribute 4 into (y + 5), giving you the answer 4y + 20.