![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqDXWEpQGAZFP7000gKyB6cQ2gxaTSb6HFOFhX8ViBG74D2hCYjgsucffpdoYnl-CMFKFobkRTDNYiK5iK3IHNaAX-XUvIooW6qfKgD1ZvdvVgNhIKFbRsfgL9TvT9XKUyr-ns1SLPLoQ/s1600/1.png)
Example
The price of tea is decreased by 15%. How much % consumption of sugar is increased so that the expenditure of sugar is same?
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFiNFYdRi-bbtMh1ww3qL4Vj7wez2clJ-bX4z_KaghdD_LZMqfgWBre4iEQg-Xs58amFr3Qhx8Kl3N6CARFKivTrmM21p8HKCqOygg5Ojqr7IT1PrvQ7tyLYP0HAW5OA1aDaR0kDPurko/s1600/2.png)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLdTIEVUibrb_3mXQ3fUp0qIlTtEmau6WpCtBEx8AQw5U4aqsJwa7onDkfLwNiMoxChJKVR2G-1rH8-wO8fqH1dVsrfiB3oKrHqUssQK9lJ6rnOMoL7d78-dmxTM-H2nTNoLJvSeC8nsw/s1600/3.png)
2. If a number is increase/ decrease by X% and then increase/ decrease by Y% so ![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitnKIs6E0X2kcAYXlStQ6eVZRQVdZ5_ZQzwL0oQzO8If4dFsXSxkN0XLHkHRUo2WGrroIxzZPmkvbHT_c3zPI2ajOmWxlLiXIkWxPmGDtjl7zjbPj7_eNhPC3D40SMPTAuE8eMKD55_q8/s320/1.png)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFiNFYdRi-bbtMh1ww3qL4Vj7wez2clJ-bX4z_KaghdD_LZMqfgWBre4iEQg-Xs58amFr3Qhx8Kl3N6CARFKivTrmM21p8HKCqOygg5Ojqr7IT1PrvQ7tyLYP0HAW5OA1aDaR0kDPurko/s1600/2.png)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLdTIEVUibrb_3mXQ3fUp0qIlTtEmau6WpCtBEx8AQw5U4aqsJwa7onDkfLwNiMoxChJKVR2G-1rH8-wO8fqH1dVsrfiB3oKrHqUssQK9lJ6rnOMoL7d78-dmxTM-H2nTNoLJvSeC8nsw/s1600/3.png)
=17.65%
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitnKIs6E0X2kcAYXlStQ6eVZRQVdZ5_ZQzwL0oQzO8If4dFsXSxkN0XLHkHRUo2WGrroIxzZPmkvbHT_c3zPI2ajOmWxlLiXIkWxPmGDtjl7zjbPj7_eNhPC3D40SMPTAuE8eMKD55_q8/s320/1.png)
Example
If a number is increased by 10% and then decreased by 5%. Find the total % change in that number.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEje3O5bbLMndPetJ4broBUF3GZxjPOQx2cQH-HqA1KM-9ea0luxcPjlJ8-0g32BopHuf_UI2A6jkC6zvx7NBQcv_NxIv_n8LQDnVtExirHe63WD2AV0T2imcniFI2XUc0Gkg61ZmRLaCf4/s1600/2.png)
=10-5-.5
=4.5%
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEje3O5bbLMndPetJ4broBUF3GZxjPOQx2cQH-HqA1KM-9ea0luxcPjlJ8-0g32BopHuf_UI2A6jkC6zvx7NBQcv_NxIv_n8LQDnVtExirHe63WD2AV0T2imcniFI2XUc0Gkg61ZmRLaCf4/s1600/2.png)
=10-5-.5
=4.5%
Some more important Examples:
Example 1.
20% of a number is 60 less than three-fifth of that number. Find that number.
Solution: x×3/5 - x×20% = 60
x×3/5 - x×1/5 =60
x×2/5=60
x=150
Solution: x×3/5 - x×20% = 60
x×3/5 - x×1/5 =60
x×2/5=60
x=150
Example 2.
The length of rectangular is increased by 8% while the width is increased by 10%. What is the % change in this area?
Solution:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlgsHhhUQNLE9BZMqTJgE2-vXgmF4YWEyN15OkMArBbyF0rmIZzndos-ujFAxMcX7uvyfXs9dHkK40CMJlBR02hHzEbNzOujceQrBR4TDXRw6dBaKmR5nIY-5Hy2EhtcN6pau4Sr6RtP4/s1600/2.png)
=18.8%
Solution:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlgsHhhUQNLE9BZMqTJgE2-vXgmF4YWEyN15OkMArBbyF0rmIZzndos-ujFAxMcX7uvyfXs9dHkK40CMJlBR02hHzEbNzOujceQrBR4TDXRw6dBaKmR5nIY-5Hy2EhtcN6pau4Sr6RtP4/s1600/2.png)
=18.8%
Example 3.
Mohan gave 40% of his money to his wife and gave 20% of the remaining money to his daughter and he donated half of the amount he left and now he has only 1500 rs. How much money did Mohan have initially?
Solution:
Solution:
Let the total money= x
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzYXGB9Di8c96wtGvlzj4Gvkwyl7XcR8DG1BykhNeULSl0uat0nmgQF4n0kmcuhZmlPJSbq12TmkWbcZRgErT28UEDyVC4QnQCQ9yRxHPHJKHa_gNU4hkEFDuWRloAQxOlIAACe9LgBH0/s1600/3.PNG)
X×60%×80%×50%=1500
X=6250 rs.
X×60%×80%×50%=1500
X=6250 rs.
Example 4.
In the three sided election A gets 12% of the total votes and remain on 3rd position, B gets 46% of votes and he wins the election by 1200 votes, C remains on 2nd position. Find the total votes.
Solution:
Solution:
Two numbers are respectively 20% and 35% more than 3rd number. 2nd number is how much % more than 1st.
Solution:
Solution:
3rd number= 100, 1st number= 120, 2nd number= 135
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_oGkJYGUr1cjICzCNJZ_Bfr6Sy7x1bGpZ_P06RaAoNRK8TrshGzbZ_wVW_svkjqoRov2CaYdU6gUPQIsuauSZ66l6s6gN5AlsjxiWpaGKqM7-w5XICcVxvIUC-ucQGHrjVq2qaoRGA5M/s1600/5.png)
=15/120×100
=12.5%
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_oGkJYGUr1cjICzCNJZ_Bfr6Sy7x1bGpZ_P06RaAoNRK8TrshGzbZ_wVW_svkjqoRov2CaYdU6gUPQIsuauSZ66l6s6gN5AlsjxiWpaGKqM7-w5XICcVxvIUC-ucQGHrjVq2qaoRGA5M/s1600/5.png)
=15/120×100
=12.5%
Example 6.
In an examination 33% of total marks are passing marks. 1 candidate gets 150 marks and failed by 48 marks. Find the total marks.
Solution:
Solution:
Total passing marks= 150+45 =198
33% = 198
100% = 600
Total marks= 600
33% = 198
100% = 600
Total marks= 600
Example 7.
In an examination 35% of the total marks are passing marks. 1 candidate got 120 marks and failed by 5% marks. Find the passing marks.
Solution:
Solution:
Candidate got 35%- 5%
30% = 120
100% = 400
30% = 120
100% = 400
Example 8.
In an examination 1 candidate got 30% marks and failed by 40 marks another candidate secure 40% marks and got 40 marks more than the passing marks. Find the passing marks.
Solution:
Solution:
X×30%+40= X×40%-40
X×40%-X×30% = 40+40
X×10%=80
X=800
Passing marks = 800×30% + 40
=240+40
=280
X×40%-X×30% = 40+40
X×10%=80
X=800
Passing marks = 800×30% + 40
=240+40
=280
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