What is the difference between 13:40 and 17:15

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?

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer