The decay constant of radium 226 is 43 1064 000043 How long

The decay constant of radium 226 is -4.3* 106-4 = -0.00043. How long does it take for 20 grams of radium to be reduced to 3 grams? A (t) = A_0e^kt (t-years).

Solution

A(t)=A₀e^kt

3=20 e^-.00043t

3/20=e^-.00043t

ln(3/20)=-.00043t

t=4411.9 years

And that\'s the answer .