Question

The half-life of a radioactive kind of radium is 11 days . How much will be left after 22 days , if you start with 64 grams of it?

Answer 1

Half- life means after the half life period, only half the original amount remains.

So after 11 days half of 64 grams remain: 64 / 2 = 32 grams,

The after another 11 days, which would be 22 days total ( 11x 2=22) only 32/2 = 16 grams would remain.