The concentration C (in mg/dl), of a certain antibiotic in a patient's bloodstream is given by C (t) = 50 t / (t^2 + 25) where t is the time (in hours) after taking the antibiotic. What is the concentration 5 hours after taking the antibiotic?

Given that the concentration has been modeled by the formula:

C (t) = 50t / (t^2+25)

where:

t is time in hours.

The concentration after 5 hours will be given by:

t = 5 hours

plugging the value in the equation we get:

C (5) = (50 (5)) / (5^2+25)

simplifying the above we get:

C (5) = 250 / (50) = 5 mg/dl

Answer: 5 mg/dl