Problem
46. An experiment is conducted relating the time in hours and the amount of a drug remaining in the bloodstream. The following data points were recorded: \( (1,10),(3,9),(5,7),(6,5),(7,3),(9,1) \). How many milligrams of the drug remain in the bloodstream after 5 hours? (a) 3 milligrams (b) 7 milligrams (c) 6 milligrams (d) 9 milligrams.
Solution
Step 1 ：\(\text{Given the data points, find the value of the drug remaining in the bloodstream at 5 hours.}\)
Step 2 ：\(\text{Data point at 5 hours is }(5,7)\).
Step 3 ：\(\boxed{\textbf{(b) 7 milligrams}}\)
