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

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

Step-by-step 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 (1.1p - p)/(1.1p) \ x \ 100`

`\rightarrow \sf (0.1p)/(1.1p) \ x \ 100`

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