$1.$ Three different processors P$1,$ P$2,$ P$3$ executing the same set of instructions. P$1$ has a $3$ GHz clock rate and a CPI of $1\mathrm{.}5.$ P$2$ has $2$ GHz clock rate and CPI of $1\mathrm{.}2.$ P$3$ has $4$ GHz and CPI of $2\mathrm{.}4.$