The mean of a set of five numbers is 4.8. given that the sixth number is x and the mean of these six numbers is 5.5, find the value of x.

How do i do this activity, is appreciated

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?

Adolphin is swimming with her friend. the dolphin jumps to a height of 4.54.54, point, 5 meters above the surface of the water as her friend swims 9.89.89, point, 8 meters directly below her. what is the position of the dolphin's friend relative to the surface of the water? meters