In the case of simultaneous memory access organization, Average access time( Tavg) =H1T1+(1-H1)H2T2 ,in the case of two level memory organization H2 =1 (there will be 100% hit)
so ,Tavg =.98 *12 +(1-.98)*1*1500 ns =41.76 ns
In the case of hierarchical memory access organizationn ,Average access time( Tavg) =H1T1+(1-H1)H2(T1+T2),in the case of two level memory organization H2 =1 (there will be 100% hit)
so, Tavg =.98 *12 +(1-.98)*1*(12+1500 ) ns =42 ns
so, multi-level memory organization can be either simultaneous memory access organization or hierarchical memory access organizationn,it depends on information given in the question but if not clear from question ifself then solve for both cases and then check the right answer from options(sometimes this strategy needed).