Question

15. The price of petrol goes up by 10%. By how much per cent must a motorist reduce the consumption of petrol so that the expenditure on it remains unchanged? 16. Then​

Answer 1

Answer:

So, the motorists have to reduce the consumption of petrol by 9.09 %, so that the expenditure on it remains unchanged.

Answer 2

Answer:

Solution :

Let the initial price of petrol be Rs. x

Then, price after increase of 10 % = 100 + (100*10)/100

= 100 + 10

Price after increase of 10% = Rs. 110

Now,

Reduction in consumption of petrol in percent = [{(110 - 100))*100]/110

(10*100)/110

⇒ 100/11

→ 9.09%

So, the motorists have to reduce the consumption of petrol by 9.09 %, so that the expenditure on it remains unchanged.