A girl spends 80% of her income. If her income increases by 18% and her expenditure increases by 25%. then what is the percentage increase or decrease in her savings (correct to one decimal place)?

Options

A. 5%, decrease
B. 10%, decrease
C. 10%, increase
D. 5%, increase

Answer

To solve the problem step by step, let's denote the initial income and expenditure of the girl.

1. **Initial Income and Expenditure**:
- Let the initial income = 100 (for simplicity).
- Since she spends 80% of her income, her initial expenditure = 80% of 100 = 80.
- Therefore, her initial savings = Income - Expenditure = 100 - 80 = 20.

2. **Income Increase**:
- Her income increases by 18%.
- New income = Initial income + (18% of Initial income) = 100 + (0.18 * 100) = 100 + 18 = 118.

3. **Expenditure Increase**:
- Her expenditure increases by 25%.
- New expenditure = Initial expenditure + (25% of Initial expenditure) = 80 + (0.25 * 80) = 80 + 20 = 100.

4. **New Savings**:
- New savings = New income - New expenditure = 118 - 100 = 18.

5. **Change in Savings**:
- The change in savings = New savings - Initial savings = 18 - 20 = -2.
- This indicates a decrease in savings.

6. **Percentage Change in Savings**:
- Percentage change in savings = (Change in savings / Initial savings) * 100 = (-2 / 20) * 100 = -10%.

Thus, the percentage decrease in her savings is **10.0%**.