The temperature of a city changed by -20 degrees Celsius over a 4-week period. The temperature changed by the same amount each week. Expression A: Write an expression to show the average change in the temperature of the city each week. Part B: Simplify the expression an explain, using words, what your answer means.

Point $(x, y)$ is randomly picked from the rectangular region with vertices at $(0,,,2010),$ and $(0,2010)$. what is the probability that $x > 7y$? express your answer as a common fraction.

The weight of full–grown tomatoes at a farm is modeled by a normal distribution with a standard deviation of 18.4 grams. the 95 percent confidence interval for the mean weight of the tomatoes is calculated using a sample of 100 tomatoes. what is the margin of error (half the width of the confidence interval)?

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?