A radioactive substance decays at a rate of 25% every 10 years. Which equation represents the amount of the substance (S) remaining from 100 grams after 300 years?

Respuesta :

Answer:

[tex]y = 100 * (0.75)^{30[/tex]

Step-by-step explanation:

Given

[tex]a =100[/tex] --- Initial Amount

[tex]r= 25\%[/tex] every 10 years

Required

The remaining amount after 300 years

To do this, we make use of:

[tex]y = a(1 - r)^T[/tex]

Where

r = decay rate

T = the period of decay

In 300 years, there are 30 periods of 10 years.

i.e.

[tex]T = \frac{300}{10}[/tex]

[tex]T = 30[/tex]

[tex]y = a(1 - r)^T[/tex]

[tex]y = 100 * (1 - 25\%)^{30[/tex]

[tex]y = 100 * (1 - 0.25)^{30[/tex]

[tex]y = 100 * (0.75)^{30[/tex]