The CISC processor runs at a $2$ GHz clock rate and the RISC processor runs at a $2\mathrm{.}5$ GHz clock rate. The CISC machine code program executes a total of $180$ billion instructions and has an average CPI of $4\mathrm{.}2.$ The RISC machine code program executes a total of $240$ billion instructions and has an average CPI of $1\mathrm{.}6.$