A CPU has two levels of cache. Its clock rate is $4$GHz$.$ The base CPI is $0\mathrm{.}5.$ The level$-1$ cache access is included in the base CPI. The level$-2$ cache access time is $6\mathrm{.}25$ns$.$ The main memory access time is $37\mathrm{.}5$ns$.$

If the level$-1$ cache miss rate is $0\mathrm{.}05$ and the level$-2$ cache miss rate is $0,$ what is the effective CPI?

If the level$-1$ cache hit rate is $0$ and the level$-2$ cache miss rate is $0\mathrm{.}15,$ what is the effective CPI?

If the level$-1$ cache miss rate is $0\mathrm{.}05$ and the level$-2$ cache miss rate is $0\mathrm{.}15,$ what is the effective CPI?

Round the answers to the hundredth. The hundredth digit must be present even if it is zero. Keep more digits for intermediate results to avoid large accumulated errors.