Consider a DRAM memory. Assume that:

The memory has a single level of cache

Checking the cache takes zero time

Cache access time is 2ns

DRAM access time is 30ns

Accessing memory on a miss requires accessing the DRAM then accessing the cache to retrieve

The current effective access time is 11ns

Given all of this:

If the current effective access time is 11ns, what is the current hit rate? What would the effective access time be if we subtracted a flat 5% from the hit rate? What hit rate would we need for an effective access time of 3ns?