Question

A cup of coffee contains 130 mg of caffeine. If caffeine is eliminated from the body at a rate of 11% per hour, how much caffeine will remain in the body after 3 hours?

Answer 1

Answer:

91.646 mg ( approx ) of coffee will remain.

Step-by-step explanation:

Given,

Initial quantity of coffee in the body, a = 130 mg,

Rate of decreasing per hour, r = 11 %,

Thus, the remained quantity of coffee after 3 hours,

$A=a(1-\frac{r}{100})^3$

$=130(1-\frac{11}{100})^3$

$=130(\frac{89}{100})^3$

$=130(0.89)^3$

$=91.64597\approx 91.646\text{ mg}$

Answer 2

A=p (1-r)^t
A=130×(1−0.11)^(3)
A=91.65