The amount of water lost each day forms a geometric progression (GP) with the first term, \(a = 10\), and common ratio, \(r = 1.1\).

The sum of the first 30 terms of a GP is given by:

\(S_{30} = \frac{a(r^{30} - 1)}{r - 1}\)

Substituting the values, we have:

\(S_{30} = \frac{10(1.1^{30} - 1)}{1.1 - 1}\)

Calculating this gives \(S_{30} = 1645\).

The total water lost after 30 days is 1645 litres.

The percentage of the original 2000 litres left in the tank is:

\(\text{Percentage left} = \frac{2000 - 1645}{2000} \times 100\)

\(= 17.75\%\)