Shirley is 21 years older than Laura. In six years, Shirley will be twice as old as Laura. How old are they each now? Solve by first creating a system of equations and then solving the system of equations. Be sure to define clearly each variable used.

For a science project, a high school research team conducted a survey of local air temperatures. based on the results of the survey, the found that the average temperatures were around 10 degrees higher than expected. this result was wrong. the trouble with the survey was that most of the locations were exposed to direct sunlight and located over asphalt or sand, which resulted in higher temperatures than normal. this is a classic example of an error in which phase of inferential statistics?