Solve the Problem $y = y _ { 0 } e ^ { - 0.40 t }$

Multiple Choice

Solve the problem.
-The amount of a certain drug in the bloodstream is modeled by the function $y = y _ { 0 } e ^ { - 0.40 t }$ , where y0 is the amount of the drug injected (in milligrams) and t is the elapsed time (in hours) . Suppose that 10 milligrams are
Injected at 10:00 A.M. If a second injection is to be administered when there is 1 milligram of the drug present in
The bloodstream, approximately when should the next dose be given? Express your answer to the nearest
Quarter hour.

A) 5:45 P.M
B) 5: 30 P.M
C) 3:45 P.M
D) 12:30 P.M