Suppose that we can improve the floating-point instruction performance of a machine by a factor of 15 (the same floating-point instructions run 15 times faster on this new machine). What percent of the instructions must be floating point to achieve a Speedup of at least 4? Suppose a program runs in 100 seconds on a machine, with multiply responsible for 80 seconds of this time. How much do we have to improve the speed of multiplication if we want the program to run 4 times faster?" How about making it 5 times faster?