Question

The price of petrol has increased by 30%. By how much per cent must Mr Sinha reduce his consumption of petrol so that his expenditure on petrol does not increase?
please explain step by step​

Answer 1

Answer:

To elaborate by an example, consider the cost of petrol as 70 rupees/ litre and Mr. sinha refills only 70 rupees petrol, no matter the increase or decrease in price.

Now if the cost is increased to 20% it will be

= 70+(30%*70)

=91 rupees/ litre.

So the price difference is 91-70=21 rupees/ litre.

Now if the expenditure should be same so that Mr. sinha will pay only 70 rupees, then he must be consuming less petrol. ( i.e lesser than 1 litre.). So he will consume :

i.e (70 rupees / 91 rupees)*1 litre= 0.864 litre.

Reduction in quantity of petrol consumed by Mr. sinha= 1 litre –0.864litre= 0.136 litre.

Therefore percentage reduction of petrol consumption by Mr. sinha

=(1–0.864)*100= 13.6 %

Step-by-step explanation:

so that his expenditure on petrol does not increase is 13.6 %