**Solution: **

Let *x* litres of water is required to be added.

Then, total mixture = ( *x* + 1125) litres

It is evident that the amount of acid contained in the resulting mixture is 45% of 1125 litres.

This resulting mixture will contain more than 25% but less than 30% acid content.

∴30% of (1125 + *x* ) > 45% of 1125

And, 25% of (1125 + *x* ) < 45% of 1125

30 % of (1125 + *x* ) > 45% of 1125

25% of (1125 + *x* ) < 45% of 1125

∴562.5 < *x* < 900

Thus, the required number of litres of water that is to be added will have to be more than 562.5 but less than 900.