$1.[20$ marks$]$ Amdahl's Law

On a serial computer, portion A of program Q takes $12$ s$,$ while portion B takes

$98$ s$.$ On a parallel computer, portion A speeds up by a factor of $2\mathrm{.}135,$ while

portion B speeds up by the number of processors. If a fractional number P$*$ of

processors exactly achieves a speedup that is a fraction f $<1$ of the

theoretical maximum speedup, then P$*$ processors also exactly achieve a run

time that is a fraction $1/$f $>1$ of the theoretical minimum run time, and

conversely.