The half-life of Palladium-100 is 4 days. After 16 days a sample of Palladium-100 has been reduced to a mass of 1 mg.

Question

The half-life of Palladium-100 is 4 days. After 16 days a sample of Palladium-100 has been reduced to a mass of 1 mg.

What was the initial mass (in mg) of the sample?   

What is the mass 6 weeks after the start? 

Answer 1

1 = a₀(0.5)^16/4

1 = a₀(0.5)⁴

1 = a₀(0.0625)

16 = a₀

Or thinking about the meaning of half-life

1, 2, 4, 8, 16

A = 16(0.5)^42/4