Given a cache access time of 20ns, a main memory access time of 1000ns, and a cache hit ratio of 90 percent.Assuming fetches to main memory are started in parallel with look-ups in cache, calculate the effective (average) access time of this system.(There

Given a cache access time of 20ns, a main memory access time of 1000ns, and a cache hit ratio of 90 percent.Assuming fetches to main memory are started in parallel with look-ups in cache, calculate the effective (average) access time of this system.(There is no virtual memory on this system -- no page table, no TLB). You may leave this as an expression