Arianna is standing on a dock beside a lake. She drops a rock from her hand into the lake. After the rock hits the surface of the lake, the rock's distance from the lake's surface changes at a rate of −6 inches per second. If Arianna holds her hand 7 feet above the lake's surface, how far from Arianna's hand is the rock 8 seconds after it hits the surface?

The rock is
inches away from Arianna's hand.