If a CPU's maximum voltage, V, is cut to V/n, its power consumption drops to 1/n2 of its original value and its clock speed drops to 1/n of its original value. Suppose that a user is typing at 1 char/sec, but the CPU time required to process each character is 100 msec. What is the optimal value of n and what is the corresponding energy saving in percent compared to not cutting the voltage? Assume that an idle CPU consumes noenergy at all.