Correct Answer - Option 3 : 20%
GIVEN:
savings = 25%
the increase is expenditure next year = 20 %
EXPLANATION:
let his salary be 100
\(savings = 25, \space expenditure =75\\next\space year's\space expenditure= \frac{6}{5}\times 75= 90 \\now ,\space 75\% of \space salary= 90\\increased\space salary=\frac{90}{75}\times 100=120 \\\%\space increase= \frac{120-100}{100}\times 100=20\%\)