A computer has a cache, main memory, and a disk used for virtual memory. An access to the cache takes $10$ ns $.$ An access to main memory takes $100$ ns $.$ An access to the disk takes $\backslash (10,000\backslash$mathrm$\{$~ns$\}\backslash ).$ Suppose the cache hit ratio is $0\mathrm{.}9$ and the main memory hit ratio is $0\mathrm{.}8.$ What is the effective access time $($EAT$)$ in ns required to access a referenced word on this system?