Keith has a debt of $150 at the beginning of the summer he wants to have at least $200 in the account at the end of the summer if he plans to save $75 each week what is the minimum number of weeks he'll have to work in order to meet his goal?and show how to solve it and tell me a number line

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