Answer:
a)
, b)
, c)
, d) 
Step-by-step explanation:
a) Let assume an initial mass m decaying at a constant rate k throughout time, the differential equation is:

b) The general solution is found after separating variables and integrating each sides:

Where
is the time constant and 
c) The time constant is:


The particular solution of the differential equation is:

d) The amount of radium after 300 years is:

Answer:
hope it helps ......
Step-by-step explanation:
....
have a great day
Answer:
F
Step-by-step explanation:
Answer:
V≈678.58cm³
Step-by-step explanation:
The answer would be C, 15