Question

the half-life of iodine-131 is 8.1 days. how much time had passed if i only have one-fourth of the original sample?​

Answer 1

16.2 days

Step-by-step explanation:

Find the number of halflives:

1/2 * 1/2 = 1/4 so two halflives have passed

2 * 8.1 days = 16.2 days