Can somebody write out and explain who to solve these problems ? i need asap in advance

Can someone me my sister? she is in third grade. 50 points and brainlist! ones that are not answered. plz and thx!

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

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?