A jar contains n nickels and d dimes. There are 19 coins in the jar, and the total value of the coins is $1.35. How many nickels and how many dimes are in the jar? (Hint: Nickels are worth $0.05 and dimes are worth
$0.10.)

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