You discovered 1000 grams of an unknown element called Coolium 23 that has a half life 23 days. How long will it take for you to have 600 grams remaining.

13.8 days

Step-by-step explanation:

In this case we can solve it by means of a rule of three, knowing the amount of life for 1000 grams, it must be proportional for 600 grams, like this:

grams days

1000 23

600 x

x = 600 * 23/1000

x = 13.8

which means that for the 600 grams it would be an average life of 13.8 days.