Elian and Alberto won tickets at an arcade. When they put their tickets together they had exactly 100. Alberto won 12 tickets less than Elian. Let a be the number of tickets Alberto won and let e be the number of tickets Elian won

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