Assume that a system is using write-though cache. It has 70% write hits. The cache operates in look-aside mode with a read-hit ratio of 80%. The program run on the system is such that it has memory reference for read 70% of time and for write is 30%. The main memory cycle time is 100ns and the cache access is 20ns.(Further assume we are using no write allocate policy)

Difference between average write access time and average read access time is ______ (in ns).