Question

The price of petrol goes up 10%, by how much percent must a motorist reduce the consumption of petrol so that the expenditure on it remains unchanged ?​

Answer 1

Answer:

$\large{\sf \boxed{ \sf 9.09 \ \%}}$

Explanation:

Let the price be p,

When the price is increased by 10%,

Increased price = (100% + 10%) × p = 1.1p

So reduction percentage:

$\rightarrow \sf \dfrac{1.1p - p}{1.1p} \ x \ 100$

$\rightarrow \sf \dfrac{0.1p}{1.1p} \ x \ 100$

$\rightarrow \sf 9.090909091 \% \quad \approx \quad 9.09 \% \quad (rounded \ to \ nearest \ hundredth)$