Answer:
Step-by-step explanation:
in 6 years we know that it will be half, because that's what "half life" means
in 3 years it's only loses 1/2 * 1/2 = 1/4 of it's mass
in 1 year it's only loses 1/6 * 1/2 = 1/12 of it's mass
from that we can make the formula that
current weight of radium = Wr
Mass of radium orginal = Mo
year of time = t ( must be in years, not days, months or weeks )
Wr = (1/12)*t* Mo
