Let the initial salary be $S$ and the initial savings be $0.1S$. After a 12% increase, the new salary becomes $S' = S + 0.12S = 1.12S$. If expenditure increases by 10%, new expenditure becomes $E' = E + 0.1E = 1.1E$. Savings after the increase become $S' - E'$; assuming $E = S - 0.1S = 0.9S$, we find the new savings are $1.12S - 0.99S = 0.13S$. The change in savings is $0.13S - 0.1S = 0.03S$, which is a 30% increase from the initial savings of $0.1S$.