Erin is buying produce at a store. she buys c cucumbers at $0.99 each and a apples at $0.79 each. what does the expression 0.99c+0.79a represent

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