Given the following two$-$level memory system:

Level $1$ memory access time $=$ TL$1$

Level $2$ memory access time $=$ TL$2$

Average time to access a word from mem $=110$ ms

TL$1=$ TL$2/100$

Hit Ratio $=0\mathrm{.}9(90\%)$

Time to find a word in any level of the memory $(0$ ms$).$

Calculate TL$1.$ Do not include units in your answer. You MUST show work to receive credit. Clearly state the formula you are using to solve this.