The price (per litre) of petrol increases by 50%. By what percent should its consumption be reduced such that the expenditure on it increases by 32% only?

Correct option is B

Given:

Price per litre increases by 50%

Expenditure increases by 32%

Formula Used:

Expenditure = Price × Consumption

Solution:

Let the original price = 100, original consumption = 100

New price = 150

New expenditure = 132

New consumption = $$\frac{132}{150}$$ = 0.88 or 88%

Reduction in consumption = 100% − 88% = 12% 

Alternate Solution: ​

Reduction in consumption;

= $$\frac{150-132}{150}\times 100 = \frac{18}{150} \times 100 = 12\%$$