The half-life of iodine-131 is 8 days. How many milligrams of iodine-131 remain after 24 days if the original amount was 4.00 mg?
A. 1.33 mg
B. 0.667 mg
C. 0.500 mg
D. 0.444 mg

The correct answer is - C. 0.500 mg.

Explanation:

In this case, the half-life of the iodine-131 is 8 days and the initial amount is given 4 mg. According to this after every 8 days, half of the initial value of the iodine-131 remains only.

8 days or 1st half-life = A(i)* 1/2

16 days or two half-life = A(i)* 1/4

24 days or three half-life = A(i)* 1/8

and the remaining amount A would be

= A(i)*1/2^n

= 4 * 1/2^3

= 4 *1/8

= 0.500 mg

answer; i believe that the correct answer is (a); a large rock being weathered by wind and rain;

i wish i could but this one is weird give me abc and i can solve it.