Salma gives a cashier $20 bill. She is buying an item for $9.85. How much money should salma get back

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x

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