Answer:
the amount of radioactive material in the vault after 140 years is 190 pounds.
Step-by-step explanation:
The given model for the amount of pounds of a particular radioactive material is
f(x) = 500(0.5)^(x/100)
where
Therefore, the amount of radioactive material in the vault after 140 years will be
f(140) = 500(0.5)^(140/100)
f(140) = 189.5 pounds
This answer rounded off to the nearest whole number will be
f(140) = 190 pounds
Therefore, the amount of radioactive material in the vault after 140 years is 190 pounds.