The half-life of a radioactive substance is 20 years. If you start with some amount of this substance, what fraction will remain in 120 years?

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z