6.8: Two problems
Problem 265 Several identical tanks of water sit on a horizontal base. Each pair of tanks is connected with a pipe at ground level controlled by a valve, or tap. When a valve is opened, the water level in the two connected tanks becomes equal (to the average, or mean, of the initial levels). Suppose we start with tank T which contains the least amount of water. The aim is to open and close valves in a sequence that will lead to the final water level in tank T being as high as possible. In what order should we make these connections?
Figure 11: A (rooted) binary tree.
Problem 266 I have two flasks. One is ‘empty’, but still contains a residue of a dangerous chemical; the other contains a fixed amount of solvent that can be used to wash away the remaining traces of the dangerous chemical. What is the best way to use the fixed quantity of solvent? Should I use it all at once to wash out the first flask? Or should I first wash out the flask using just half of the solvent, and then repeat with the other half? Or is there a better way of using the available solvent to remove as much as possible of the dangerous chemical?