Find y when x equals 10 if y equals eight what x equals 20

If you could answer these your a life saver

Complete the steps to find 4.830 ÷ 5

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