How do I find x?
I don’t understand this

Asurvey of 45 teens found that they spent an average of 25.6 hours per week in front of a screen (television, computer, tablet, phone, based on the survey’s sample mean, which value could be the population mean? 2.3 hours 27.4 hours 75.3 hours 41.5 hours

Point a is at 12, and point d is at 56. point c is midway between a and d, and point b is midway between a and c. which of these is the coordinate of b?

Find the volume of the wedge cut from the first octant by the cylinder z=12-3y^2 and the plane x+y=2.