Explanation:

- Scenario: Petrol price increases by 7%. You want to keep your spending unchanged.

- Problem: How much to reduce consumption in percentage terms?

Solution:

- Price Increase: 7% more expensive means you can afford 7% less quantity with the same budget.

- Math Approach: Let $x$ be the consumption reduction percentage.

- Use $\frac{100}{107}\approx 0.934579$.

- This means about 93.4579% of original consumption to keep cost unchanged.

- Reduction: $100-93.4579\mathrm{\%}=6.5421\mathrm{\%}$.

Options Evaluation:

- Option 1: 6 58/107% ˜ 6.5421%

- Option 2: 5 11/107%

- Option 3: 3 49/107%

- Option 4: 4 99/107%

Correct Answer: Option 1: 6 58/107%