Assume that a benchmark program executes in $\backslash ([\backslash$mathbf$\{$X$\}]\backslash )$ seconds on a reference machine A $.$ The same program executes on systems B$,$ C$,$ and D in $360,540,$ and $210$ seconds, respectively.

a$.$ Show the speedup of each of the three systems under test relative to A$.$

b$.$ Now show the relative speedup of the three systems. Comment on the three ways of comparing machines $($execution time, speedup, relative speedup$).$