it is given that L1 and L2 for caches for most of the questions i have seen whenever they are talking about levels it refers to hiearachial structure :
you can use any formulae:
hit rate of L1 cache=h1
hit rate of L1 cache=h2
access time of L1 cache=t1
access time of L2 cache=t2
access time of MM=t3
h1*(t1)+(1-h1)*h2(t1+t2)+(1-h1)*(1-h2)*(t1+t2+t3)
or
t1+(1-h1)*{ t2+(1-h2)*t3 }
solving by 1:
0.1*10+0.9*0.2*(10+20)+0.9*0.8*(10+20+10000). all units are in ns
=7228 ns
for 1000 logical address it will take 1000*7228ns==7228 micro sec
[P.S - answer will be 7228000 in ns please check the question again and correct me if i am wrong]