Amusic teacher sells piano lesson packages which package has the lowest ratio of cost to number of lessons

An animal shelter has 21 puppies. if the puppies are 28% of the total dogs and cat population how many dogs and cats are in the animal shelter

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

Use set builder notation to represent the following set: { -3, -2, -1, 0}