Anu spends 68% of her monthly income. If her monthly income increases by 20% and her monthly savings increase by $9\frac{3}{8}$%, then the percentage increase in her monthly expenditure is:

25%

68% = \(\frac{17}{25}\) , 20% = \(\frac{1}{5}\) & 9\(\frac{3}{8}\)% = \(\frac{3}{32}\)

Let the income  = 100x

Expenditure  = 100x ×\(\frac{17}{25}\) = 68x

Savings  = 100x - 68x = 32x

New income = 100x ×  \(\frac{6}{5}\) = 120x

New savings  = 32x +  \(\frac{3}{32}\) × 32x = 35x

New expenditure  = 120x - 35x = 85x

Increased expenditure = 85x - 68x = 17x

Percentage increased expenditure = \(\frac{17x}{68x}\) × 100 = 25%