After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1982, the hay in that country was contaminated by a radioactive isotope (half-life 8 days). If it is safe to feed the hay to cows when 11% of the radioactive isotope remains, how long did the farmers need to wait to use this hay?

25.48 days

Step-by-step explanation:

For a radioactive substance, the Amount of the substance remaining A(t) is modeled by the equation

where

In the given problem:

Half Life of the Radioactive Isotope = 8

Initial Amount, =100%=1

A(t)=11% =0.11

Therefore substituting in the model above:

The farmer need to wait for 25.48 days

hey! so 1 (25) out of 4 (100) is 25 so your answer is 25%. it's like quarters!