we need to find the number of WAIT STATES... i.e. the amount of time we have to make CPU wait such that memory is ready with the data that CPU would need, by that time. means -- at the time CPU needs data from memory the data should be present (after having sent from memory and crossed the intermediate circuitry) SINCE, CPU is faster and MEMORY Is slower so we have to make CPU wait(i.e. ADD WAIT STATES) Here, 33MHz CPU means cycle time of CPU is 30.30 ns( since 33MHz= 1/(33*10^6) seconds =30.30 ns) thus CPU wants data after every 30.30 ns but memory can make it available only after 60ns+10ns(memory cycle time+circuit delay)= 70 ns Now, >make CPU wait by adding 1 WAIT STATE(i.e. add 30.30 ns to its making demand of data) after adding 1st WAIT state, CPU will need data after 60.60 ns.. since memory cant make data available still...so >make CPU wait by adding 1 more WAIT STATE(i.e. add 30.30 ns to its making demand of data) after adding 2nd WAIT state , CPU will need data after 90.90ns ...since now memory has already made data available by 70ns ...so no more waiting for CPU and CPU will continue with its work... Thus, we have to add 2 WAIT STATES ........(ANSWER)