Final answer:
To find the amount of the painkiller remaining in the blood 1 hour after swallowing 400 mg, consider the half-life of the painkiller. The remaining amount can be calculated as the initial amount multiplied by the fraction of the half-life that has passed. In this case, the amount remaining is 50 mg.
Step-by-step explanation:
To find the amount of the painkiller remaining in the blood 1 hour after swallowing 400 mg, we need to consider the half-life of the painkiller. The half-life is the time it takes for half of the substance to decay or be eliminated from the body. Let's assume the half-life of the painkiller is 3 hours.
After 1 hour, the painkiller will have gone through 1/3 of its half-life. So, we can calculate the remaining amount as follows:
Remaining amount = Initial amount × (1/2) × (1/2) × (1/2) = 400 mg × (1/8) = 50 mg.
Therefore, the amount of the painkiller remaining in the blood 1 hour after swallowing 400 mg is 50 mg.