Answer with good high level explanation please

A certain program makes $176,000,840$ data memory accesses $($reads or writes$).$ Each

memory access takes $128ns.$ To improve performance, a proposal is made to use a data

cache for the system with an access time of $10ns.$ The cache has a hit ratio of $90\%.$

a$)$ What is the total number of nano$-$seconds required to perform all $176,000,840$ data

accesses if the cache operates in look$-$through mode?

b$)$ What is the total number of nano$-$seconds required to perform all $176,000,840$ data

accesses if instead the cache operates in look$-$aside mode?