Ok. This is the question I got from a friend of the family. There is a conically shaped bin in which sand is poured in at a rate of 2.4 m3 per minute. The sand escapes out the bottom of the conically shaped bin at 0.8 m3 per minute. The opening at the top has a radius of 5 m and the opening in which the sand is escaping is 0.5 m. The question asks for the rate of depth change after 10 minutes. I took Calculus but absolutely hate word questions. Anyway the most I can figure is that they are asking for the rate of change of the height of sand in the container.