An air conditioning system can circulate 400 cubic feet of air per minute. How many cubic yards of air can it circulate per minute?

Mg remaining = (initial amount in mg) (1/2^(t/h)) where h = half-life

1.

a.
mg remaining = (500) (1/2^(3/4)
= 297.3 mg
b.
mg remaining = (500)(1/2^(8/4))
= 125 mg
2.
5 represents the time elapsed from when the medication entered the bloodstream. Assuming the medication was given at noon, add 5 hours to have 5:00 pm.

Good luck! I need sleep. XD