A water tank is draining. The volume of the water in the tank, in gallons, is a linear function of the amount of time it has been draining, in hours. It can be modeled using the equation V (t) = –12.8t + 685, where V is the volume and t is the time. Explain what the values -12.8 and 685 mean in the context of this problem.

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.