For Example: The price of sugar having gone down by 10%,sharad can buy 6.2Kg more for Rs.279.The difference between the original and the reduced price(per Kg) is:

And another example is: The price of sugar is decreased by 25%.Therefore a family increases its consumption so that the decrement in the expenditure of sugar is only 15%.if the consumption of sugar is 30Kg before the decrement, what is the consumption now.

(Q1)Due to increase in the price of sugar by 30% a man can buy 6kg less for Rs.520.then find out the original price per kg in Rs.?

Solution:Let original price=Rs 100

Now

Step-1

[Original price=Rs 100,New price=Rs130,Original quantity=130Kg,New Quantity=100Kg And Decreased quantity=30Kg]

Concept: According to Question A man can buy 6Kg less.But यहाँ पर  30Kg कम निकल रहा है,तो अब 30Kg को 6Kg बनाना होगा इसके लिए Quantity वाले part में 5 से Divide करना होगा|

[Concept in English: According to Question A man can buy 6Kg less.but here we got 30Kg less, so we will have to make 6kg, therefore, quantity divide by 5]

Step-2

price of 26 kg=Rs520

∴ Price of 1Kg=520/26

=Rs20 Ans.

Concept:[जब Expenditure same रहेगा तब इस process से solve करना है|इस Question में Expenditure same क्योंकि पहले Rs520 में जितना खरीदता था अब price increase होने से Rs520 में 6kg कम खरीद पा रहा है ]

BY TRICK:

Original price=(30×520)/(100+30)×6

=(30×520)/(130×6)

= Rs20 Ans.

(Q2)Due to a decrease in the price of sugar by 20% a man can buy 4Kg more for Rs80 then find the original price per Kg in Kg?

Solution: Let original price=Rs100

Step-1

[Original price=Rs 100,New price=Rs80,Original quantity=80Kg,New Quantity=100Kg And Increased quantity=20Kg]

Concept: According to Question A man can buy 4Kg more.But यहाँ पर  20Kg अधिक निकल रहा है,तो अब 20Kg को 4Kg बनाना होगा इसके लिए Quantity वाले part में 5 से Divide करना होगा|

[Concept in English: According to Question A man can buy 4Kg more.but here we got 20Kg more, so we will have to make 4kg, therefore, quantity divide by 5]

Step-2

the price of 16kg=Rs80

∴ price of 1Kg=80/16

=Rs 5 Ans.

BY TRICK:

Original price=(20×80)/(100-20)×4

=(20×80)/(80×4)

= Rs.5 Ans.

(Q3)A reduction of 21% in the price of wheat enables a person to buy 10.5kg more for Rs.100.what is the reduced price per Kg?

Solution: Let original price=Rs.100

Step-1

Step-2

Price of 50Kg=Rs.100

∴price of 1Kg=100/50

=Rs.2 Ans

BY TRICK:

Reduced price=(21×100)/(100×10.5)

                          =Rs.2 Ans

(Q4)The price of sugar having gone down by 10%,sharad can buy 6.2Kg more for Rs.279.The difference between the original and the reduced price(per Kg) is:

Solution: Let original price=Rs.100

Step-1:

Step-2:

(1)Original price:

Price of 90×0.62Kg=Rs.279

∴ price of 1Kg=279/(90×0.62)

=Rs.5/Kg Ans.

(2)Reduced price:

Price of 100×0.62Kg=Rs.279

∴ price of 1Kg=279/(100×0.62)

=Rs.4.5/Kg Ans

Difference=5-4.5

                     =Rs.0.5 Ans.

BY TRICK:

Original price=10×279/(100-10)×6.2

=10×279/(90×6.2)

=Rs.5/Kg

Reduced price=10×279/(100×6.2)

                             =Rs.4.5/Kg

(Q1)The price of sugar is increased by 30%.Therefore a family reduces its consumption so that the increment in the expenditure of sugar is only 10%.if the consumption of sugar is 26Kg before the increment, what is the consumption now.

Solution: We know that

∴ X=286/13

      =22Kg Ans

ROUGH:

Rs10 increased by 30% then,

=10×(100+30)/100

=Rs13

Rs260 increased by 10% then,

260×(100+10)/100

=(260×110)/100

=Rs286

BY TRICK:

Consumption=26×(100+10)/(100+30)

=26×110/130

=22Kg Ans.

(Q2)The price of sugar is decreased by 25%.Therefore a family increases its consumption so that the decrement in the expenditure of sugar is only 15%.if the consumption of sugar is 30Kg before the decrement,what is the consumption now.

Solution:

∴ X=255/7.50

      =34Kg Ans.

ROUGH:

Rs300 decreased by 15% then

300×(100-15)/100

=(300×85)/100

=255

Rs10 decreased by 25% then,

10×(100-25)/100

=(10×75)/100

=7.50

BY TRICK:

consumption:30×(100-15)/100-25

=(30×85)/75

=34Kg Ans.