The price of petrol rose by 10%. By how much percent must one reduce the consumption so that the expenditure does not increase ?

Open in App

Solution

Dear Student,

$E x p e n d i t u r e = C o n s u m p t i o n \times P r i c e H e n c e t o k e e p E x p e n d i t u r e a s s a m e C_{1} \times P_{1} = C_{2} \times P_{2} - - (1) i n i t i a l C o n s u m p t i o n C_{1} = x a n d I n i t i a l P r i c e P_{1} = y n e w \cos t P_{2} = y + 10 % o f y = y + \frac{10}{100} y = y + 0.1 y = 1.1 y n e w C o n s u m p t i o n C_{2} = x - z % o f x = x - \frac{z}{100} x p u t v a l u e s i n e q u a t i o n 1 x y = 1.1 y \times (x - \frac{z}{100} x) x y = 1.1 \times (1 - \frac{z}{100}) \times x y \frac{1}{1.1} = (1 - \frac{z}{100}) \frac{z}{100} = 1 - \frac{1}{1.1} \frac{z}{100} = \frac{1.1 - 1}{1.1} \frac{z}{100} = \frac{0.1}{1.1} z = \frac{100 \times 0.1}{1.1} = \frac{100}{11} z = 9.09 %$

Hence answer is 9.09%

Regards,

Suggest Corrections

Similar questions

In the new budget, the price of petrol rose by $10 %$ . By how much percent must one reduce the consumption so that the expenditure does not increase?

Question 1 - In the new budget, the price of petrol rose by 10%. By how much per cent must one reduce the consumption so that the expenditure does not increase?

Q. The price of petrol is increased by 25%. By how much percent should a car owner reduce his consumption of petrol so that the expenditure on petrol would not increase ?

Q. The price of sugar goes up by

30

%. By how much percent must a housewife reduce the consumption so that the expenditure does not increase?

Q. The price of pulses increased by

30 %

. By how much percent should Surbhi reduce her consumption of pulses so that her expenditure on pulses does not increase?

Join BYJU'S Learning Program