Suppose the sequential part accounts for 10% of the program's computation time. Let s_n be the program's speedup on n processors, assuming the rest of the program is perfectly parallelizable. Your boss tells you to increase the speedup by a factor of 1.25: the revised program should have a speedup s'_n > s_n*1.25. You advertise for a programmer to replace the sequential part with an improved version that runs k times faster. What value of k should you require?