21) Submarine A is sent to explore the ocean floor in the Atlantic Ocean. It descends to 126
feet below sea level, For the next 4 ½ hours, it descends further at a rate of 15 feet per hour
and then reaches its destination.
Submarine B is sent to explore the ocean floor in the Pacific Ocean. It begins its descent at
sea level and reaches the same elevation as Submarine A over the course of 6.5 hours. At
what rate does Submarine B descend? Show and explain your thinking.