Find the horizontal asymptote of the graph

3. Today you visited the R & D (Research and Development) department of a pharmaceutical manufacturer. The people in this lab have to calculate the recommended dosage of the products they are developing. Medicine is expressed as a function of the concentration in parts per million, with the potency of the dosage declining over a period of time.

The function N(t) = (0.8t + 1000 ) / (5t+4), where t=>15 gives the body concentration N(t), in parts per million, of a certain dosage of medication after time t, in hours.

a) Find the horizontal asymptote of the graph and complete the following statement: N(t) approaches ? as t approaches infinity.

b)Explain the meaning of the answer to a) in terms of the medical dosage application.