If an element has a half-life of 16.7 days, how many days to go from 1000 to 250 atoms?

how many atoms would remain after 9 half-lives if you started with 1000 atoms?

The answer to your question is:

Explanation:

a)

Data

half-life = 16.7 days

go from 1000 to 250 atoms

                                1000

                                  500         1 half life

                                  250         2 half lives

                16.7 days 1 half life

                 x             2 half lives

                x = (2 x 16.7) / 1

               x = 33.4 days        

b)

number of atoms = ?

after 9 half-lives

                            1000

                              500       1 half life

                               250       2 half lives

                               125        3 half lives

                                62.5     4 half lives

                               31.25     5 half lives

                                15.63    6 half lives

                                 7.81      7 half lives

                                 3.9       8 half lives

                                 1.95      9 half lives

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter