I have a cylindrical vat of water 3𝑓𝑡 in diameter, and a hose that fills it up at a rate of 4𝑓𝑡3𝑚𝑖𝑛. It also leaks 12𝑓𝑡3 every minute. If the vat is initially empty, how fast is the height of the water changing after 10min ?