A bag contains white marbles and red marbles, 20 in total. The number of white marbles is 4 less than 2 times the number of red marbles. How many white marbles are there? PLEASE HELP!!!

Recall that the owner of a local health food store recently started a new ad campaign to attract more business and wants to know if average daily sales have increased. historically average daily sales were approximately $2,700. the upper bound of the 95% range of likely sample means for this one-sided test is approximately $2,843.44. if the owner took a random sample of forty-five days and found that daily average sales were now $2,984, what can she conclude at the 95% confidence level?