Effective memory access time= time for address translation+ actual memory access time for accessing a word.
During address translation, we check in TLB. If the entry is not available in TLB, memory is accessed for the entry.
Once the address is translated, we access main memory to get the word.
=TLB access time+(miss rate of TLB)* memory access time+ memory access time
=20+(1-80/100)*80 +80
=20+80/5+80
=116ns.