Question

When doctors prescribe medicine, they must consider how much the drug’s effectiveness will decrease as time passes. If each hour a drug is only 95% as effective as the previous hour, at some point the patient will not be receiving enough medicine and must be given another dose. If the initial dose was 250 mg, what will the level of the dose be after 3 hours?

Answer 1

214.34 about (213.75 on calculator)

Explanation:

95% of 250=237.5

95% of 237=225.15

95% of 225=213.75

Answer 2

Answer: The level of the dose be after 3 hours= 0.03125 mg.

Explanation:

General exponential decay equation :
`y=A(1-r)^x` , where A = initial value , r= rate of decay , x =Time period.

Here, drug’s effectiveness is decreasing exponentially.

AS per given , we have

A= 250 mg

x=3

r= 95% = 0.95

Then,
`y=250(1-0.95)^3 = 250(0.05)^3=250*0.000125=0.03125`

Hence, the level of the dose be after 3 hours = 0.03125 mg.