Ta có: `A = 92 - \frac{1}{9} - \frac{2}{10} - \frac{3}{11} - ... - \frac{92}{100}`

`= (1 - \frac{1}{9}) + (1 - \frac{2}{10}) + (1 - \frac{3}{11}) + ... + (1 - \frac{92}{100})`

`= \frac{8}{9} + \frac{8}{10} + \frac{8}{11} + ... + \frac{8}{100}`

`= 8 \times (\frac{1}{9} + \frac{1}{10} + \frac{1}{11} + ... + \frac{1}{100})`

Ta có: `B = \frac{1}{45} + \frac{1}{50} + \frac{1}{55} + ... + \frac{1}{500}`

`= \frac{1}{5 \times 9} + \frac{1}{5 \times 10} + \frac{1}{5 \times 11} + ... + \frac{1}{5 \times 100}`

`= \frac{1}{5} \times (\frac{1}{9} + \frac{1}{10} + \frac{1}{11} + ... + \frac{1}{100})`

Xét `A/B,` ta được:

`\frac{A}{B} = \frac{8 \times (\frac{1}{9} + \frac{1}{10} + \frac{1}{11} + ... + \frac{1}{100})}{\frac{1}{5} \times (\frac{1}{9} + \frac{1}{10} + \frac{1}{11} + ... + \frac{1}{100})}`

`=8/(1/5)`

`=40`

Vậy tỉ số `\frac{A}{B} = 40`