Question

If the price of petrol increases from ₹90/l to ₹110/l, by what percentage does a person have to decrease his consumption so that his expenditure on petrol remains the same (approximate to two decimals)?

• A. 78.78%
• B. 25.25%
• C. 18.18%
• D. 81.81%

Answer 1

Answer:

C. 18.18%

Let the initial consumption be x litres.

Initial expenditure:
$90 \times x$

After price increase, let new consumption = y litres.

New expenditure (same as before):
$110 \times y$

Since expenditure remains same:
$90x = 110y$
$\Rightarrow y = \frac{90}{110}x = \frac{9}{11}x$

Reduction in consumption:

$x - y = x - \frac{9}{11}x = \frac{2}{11}x$

Percentage decrease:

$\frac{2}{11} \times 100 = 18.18\%$

Final Answer:

18.18% decrease