Question

By comparing the amount of carbon-14 to amount of carbon-12, one can determine approx how long ago the organism died.

The half-life of carbon-14 is 5730 years. Assume the initial quantity of carbon-14 is 600 milligrams.

the equation is
A (t)=600*(.5)^(t)
(0,600)
(1,300)
(2,150)
(3,75)
(4,37.5)
(5,18.75)
(6,9.375)
(7,4.6875)

from the table, estimate how many milligrams are left after 40,000 years. Round answer to 2 decimal places.


I'VE TRIED PLUGGING IT TO THR FORMULA, BUT IT GIVES ME A WRONG ANSWER. HELP!!

Answer 1

No, your equation cuts the amount in half every time t increases by 1.

Since the half-life is 5730 years, you want the amount to be cut by half only that often. So,

A9t) = 600(0.5)^(t/5730)

To do a sanity check on your answer, note that 40000 years is about 7 half-lives, so expect the amount to be about 1/128 of the original 600 mg, or about 4.6mg.