Which situation has a net result of zero?

- the temperature was -90 degrees f and fell 90 degrees f

- janet had $4 and gave $3 to her friend.

- high tide was 5.5 ft and now low tide is - 0.5 ft.

- the hot air balloon rose 539 feet. it then lost 539 feet of altitude.

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?

Michael is training for a marathon. in his first week he plans to run 8miles. what path should he take

Tom is the deli manager at a grocery store. he needs to schedule employee to staff the deli department for no more that 260 person-hours per week. tom has one part-time employee who works 20 person-hours per week. each full-time employee works 40 person-hours per week. write and inequality to determine n, the number of full-time employees tom may schedule, so that his employees work on more than 260 person-hours per week. graph the solution set to this inequality.