15 Water is draining from a small cylindrical tank into a larger one below it The small cylindrical tank has a radius of 4 feet and a height of 6 feet the large cylindrical tank has a radius of 8 feet and a height of 16 feet The small tank is initially full of water and the water drains out at a rate of cubic feet per second Note The volume of a cylinder is V r h A Find the volume Vs of the water remaining in the small tank as a function of time B How long does it take for the small tank to completely empty C Let z be the depth of the water in the large tank which is initially empty Compute D What fraction of the total amount of water is in the large tank at time t 6