The original mass of the radioactive sample is determined as 800 g.
How to calculate the original mass of the sample?
The original mass of the radioactive sample is calculated by applying the following formula as shown below;
The remaining mass after the decaying period = 25 g
The time of the decay = 40.35 days
The half life of the substance = 8.07 days
The original mass of the radioactive sample is calculated as;
N₀/2ˣ = N
The value of x is calculated as
x = 40.35 days / 8.07 days
x = 5
The original mass of the radioactive sample is calculated as
N₀/2⁵ = 25
N₀ = 32 x 25
N₀ = 800 g