In a game of chance there is a box filled with 20 black balls, 13 red balls, and 7 green balls. If a single ball is drawn from the box, then what is the probability that the ball
is green?

Please help me out.

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