At an electronics store, DVDs are on sale. Some DVDs cost $15.00 each and some cost $12.00 each. Bart purchased 8 DVDs and spent a total of $105.00. Write a system of equations and solve by using substitution to determine how many $12.00 DVDs Bart purchased.

He concluded that a heavier object dropped from the same height as a lighter object will land

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below.