Mario paid $30 to activate his cellular phone plus $50 per month. Type an equation: * y=50x + 30

Carlos paid $70 to activate his cellular phone plus $30 per month. Type an equation: *

y=30x+70

Mario and Carlos use their cellular phones for 4 months. Who pays more? *
plz help me i beg anyone

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?