Question

A doctor prescribes 400 milligrams of medicine to treat an infection. Each hour following the initial dose, 85 milligrams of the medicine are eliminated from the body. How many milligrams of the medicine will remain in the body after 3 hours?

1) 145 milligrams
2) 1450 milligrams
3) 235 milligrams
4) 2350 milligrams

Answer 1

After 3 hours, 145 milligrams of the medicine will remain in the body.

Step-by-step explanation:

To find out how many milligrams of the medicine will remain in the body after 3 hours, you subtract the amount of medicine eliminated from the initial dose. In this case, the initial dose is 400 milligrams and 85 milligrams are eliminated every hour. So, after 1 hour, 85 milligrams are eliminated, leaving 400 - 85 = 315 milligrams. After 2 hours, another 85 milligrams are eliminated from the remaining 315 milligrams, leaving 315 - 85 = 230 milligrams. Finally, after 3 hours, another 85 milligrams are eliminated from the remaining 230 milligrams, leaving 230 - 85 = 145 milligrams.