You're interested in whether tutoring is more effective when the student volunteers
to be tutored. you compare the test scores of two groups of students: those who
chose to go to after-school tutoring sessions and those who are required to go to the
sessions by the school administration. this is an example of a (an):

Tyler went to the supermarket to buy food for a food pantry. he has $36, and can carry up to 20 pounds of food in his backpack. pasta costs $1 for a 1-pound package. pasta sauce costs $3 for a 1.5 pound jar. let x = the number of packages of pasta and y = the number of jars of pasta sauce. one package of pasta is the right amount to go with one jar of pasta sauce. what is the best numbers of packages of pasta and jars of pasta sauce to buy for the food pantry? how many packages of pasta? how many jars of pasta sauce? explain your reasoning.