Question

if the price of rice is reduced by 20% one can buy 2 kg more for rs 100 used price of rice​

Answer 1

Step-by-step explanation:

Let the original price of rice be Rs.x per kg.

So he buys y kg of rice for Rs.77.

When the price becomes 0.8x he gets (y+3.5) for the same Rs.77. So the equations are

xy = 77 … (1)

0.8x*(y+3.5) = 77 … (2)

From (1) x = 77/y, put that value in (2) to get

0.8*(77/y)*(y+3.5) = 77 … (3), or cancelling 77 on both sides,

0.8*(y+3.5) = y or

0.8y +2.8 = y, or

2.8 = 0.2 y, or

y = 2.8/0.2 = 14.

From (1) x = 77/14 = Rs.5.5 per kg

Check: With 20 reduction in the price of rice its cost becomes 0.8*5.5

=Rs. 4.4/kg. And for Rs 77 he gets 77/4.4 = 17.5 kg, i.e. 3.5 kg more than previously.

So the original price for rice was Rs.5.5 per kg. Good old days which i had not seen myself even in the Fair Price Shops!

Reduction of 20% = 1/5

This means that,

Orginal price is 5 and new price is 4

And we know that quantity is inversely proportional to price,

i.e. quantity purchased by person is 4 at 5 rs and after reduction quantity purchase by person is 5 at 4 rs

Increment in quantity is 1 which us equal to 3.5 kg

Initially person was purchasing 3.5×4=14kg rice

Original price is 77/14= 5.5rs

Using this method you can find any type of question asked by examiner on this concept.

The original price of rice is Rs. 5.50 per kg

Solution:Let the original price of rice per kg be Rs. x .

So, in Rs.77, you will get 77x kg of rice.

After a reduction of 20%, the price of rice will be Rs. (x−20100×x)=4x5 .

So, in Rs.77, you will get 77(4x/5) kg of rice.

Then, finding the difference and equating it to 3.5 kg will give you the value of x .

Verification:

With original price, 14 kg of rice.

With reduced price, 17.5 kg of rice.