Give two rational numbers lying between 0.515115111511115…. and 0.5353353335….
Let a = 0.515115111511115….
b = 0.5353353335….
We observe that the second decimal place a has digit 1 and b has digit 3, therefore, a < b. So if we consider rational numbers
x = 0.52
y = 0.52052052
Then,
a < x < y < b
Hence, x and y are required rational numbers.