hi, please , i need the solution of this question from computer system architecture book for morris mano: q:the access time of cache memory is 100 ns and that of main memory 1000 ns. it is estimated that 80% of the memory requests are for read and the remaining 20% for write. the hit ratio for read access only is 0.9. a write -through procedure is used. a- what is the average access time of the system considring only memory read cycles? b-what is the average access time of the system for both read asn write requests? c-what is the hit ratio taking into consideration the write cycles? please, we are appreciating any response .