There are three lumps of a given active substance. Their activities are in the ratio of 1 : 2 : 3  now. What will be the ratio of their activities at any further date?

Suppose the activities of the lumps at present are  A1, A2  and   A3.  A1: A2 : A3=λ N1:λ N2:λ N3=1:2:3.  After time t, Let their activities be  A11 ,A21  and  A31 ∴        A11 :A21: A31=λN11: λN21: λN31=Ne −λt 1 : Ne −λt 2 :Ne −λt 3 =1:2:3.