Question

The antibiotic clarithromycin is eliminated from the body according to the formula A(t) = 500e−0.1386t, where A is the amount remaining in the body (in milligrams) t hours after the drug reaches peak concentration. How much time will pass before the amount of drug in the body is reduced to 100 milligrams? (Round your answer to two decimal places.)

Answer 1

Time(t) = 11.61 hours (Rounded to two decimal place)

Explanation:

Given: The antibiotic clarithromycin is eliminated from the body according to the formula:

`A(t) = 500e^(-0.1386t)` ......[1]

where;

A - Amount remaining in the body(in milligram)

t - time in hours after the drug reaches peak concentration.

Given: Amount of drug in the body is reduced to 100 milligrams.

then,

Substitute the value of A = 100 milligrams in [1] we get;

`100= 500e^(-0.1386t)`

Divide both sides by 500 we get;

`(100)/(500)=( 500e^(-0.1386t))/(500)`

Simplify:

`(1)/(5) = e^(-0.1386t)`

Taking logarithm both sides with base e, then we have;

`\log_e ((1)/(5))= \log_e (e^(-0.1386t))`

`\log_e ((1)/(5))=-0.1386t` [ Using
`\log_e e^a =a` ]

or

`\log_e (0.2)=-0.1386t`

`-1.6094379124341 = -0.1386t`

[using value of
`\log_e (0.2) = -1.6094379124341` ]

then;

`t = (-1.6094379124341)/(-0.1386)`

Simplify:

t ≈11.61 hours.

Therefore, the time 11.61 hours(Rounded two decimal place) will pass before the amount of drug in the body is reduced to 100 milligrams