Computer X has a cycle time of $3\mathrm{.}0$ GHz$.$ Application A has an instruction mix of

$25\%$ simple math $(1$ CPI$),$

$20\%$ branching $(2$ CPI$)$

$30\%$ multiplication $(3$ CPI$)$

$25\%$ floating$-$point $(4$ CPI$).$

The application consists of $1$ million instructions.

A: Calculate average CPI

B: Calculate the CPU time on Computer X$.$