At one bank $100 deposited into an account will after one year gain $3.50 in interest. What is the interest rate for this account? Explain or show your reasoning.

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