A program spends 60% of its execution time doing floating-point arithmetic. Of the floating-point operations in this program, 90% are executed in parallelizable loops. a. Find the improvement in running time if the floating-point hardware is made twice as fast. b. Find the improvement in running time if we use two processors to run the program's parallelizab loops twice as fast. c. Find the improvement in running time resulting from both modifications a and b.