Question

If a price of milk is increased by 30% find by how much percent must a house holder reduce his consumption of milk so as not to increase the expenditure

Answer 1

Let the price of milk be Rs 100/ ltr

And let the consumption of milk be y ltrs

Therefore, expenditure on milk = Rs 100y

Increase in price = 20%

Increased price = Rs 120

New expenditure remains the same = Rs 100y

Expenditure/New price = New consumption

100y/120 = 5/6 y

Difference in consumption = y - 5/6 y = 1/6 y

Therefore % decrease in consumption

= 1/6 y ×1/y × 100

=100/6

= 16.67%

Answer 2

Answer:

Required percentage is $23 \frac{1}{13} \%.$

Step-by-step explanation:

Let original rate of milk =Rs 100/litres. And his family consumption is 1 litres .expenditure on milk is Rs 100.only.

New rate of milk =Rs100+30% of Rs 100

$100 + \frac{30}{100} \times 100 = 100 + 30 = 130$Rupees per litres.

In Rs 130 is cost of the quantity of milk=1litres

By unitary method,

1 rupees is the cost of (1/130) litres milks.

100 rupees is the cost of $\frac{1}{130} \times 100 = \frac{10}{13}$litres milks.

Reduce in consumption=$1 - \frac{10}{13} = \frac{3}{13}$litres

Now 1 litres means 100%

So,

$\frac{3}{13}$litres means $100 \times \frac{3}{ 13} = 23 \frac{1}{13} \%$