Consider a paging system with the page table stored in memory. If a memory reference takes 90 nanoseconds, how long does a paged memory reference take? If we add associative registers, and 75 percent of all page-table references are found in the associative registers (TLB), what is the effective memory reference time? (Assume that finding a page-table entry in the associative registers takes 10 ns, if the entry is there.) a. b. registers that finding a page-table