Answer:
100mg are in your system at 3pm
Explanation:
Half-life is the time necessary to decrease the initial amount of a substance in the half.
At 12:00pm, the amount of aspirin is 800mg
As half-life is 1h,
at 1:00pm, the amount of aspirin is 800mg/2 = 400mg
At 2:00pm, 400mg/2 = 200mg
At 3:00pm, 200mg/2 =