An arborist examined trees in an orchard to see if they were infected with a virus. 9 out of 90 trees were infected with the virus. what percentage of the trees were infected? write your answer using a percent sign (%)

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