Here L1(access time)=30nsec
L2(access time)=30*8=240nsec(as its 8 times slower than L1)
Avg(access time)=L1+40=30+40=70nsec
Avg(access time)=Hit in L1 i.e H1 * L1( access time) + Miss in L1 i.e(1-H1) * Hit in L2 i.eH2* L2(access time)
Here H2 hit ratio will be 1 becz page not found in L1 will always be found in L2 memory
70=H1*30+(1-H1)*1*240
H=0.809=0.81