Commercial Maths
Class 8
Increase and Decrease Percent
To calculate percentage of increase and decrease we need to use this formulas
Increase % = Actual increase x 100
Original
Decrease % = Actual decrease x 100
Original
Example 1. The price of a tablet was ₹22,000 last year. If there is a decrease of 10 %. What is the price of the tablet this year ?
Solution : Price of tablet last year = ₹22,000
Actual decrease = 10 % of ₹22,000
= ₹ 10 x 22,000
100
= ₹2,200
Price of the tablet this year = ₹(22,000 - 2200) = ₹19,800
Example 2. The population of city increases every year by 10 %. If the Population in the year 2018 is 1,18,800. What was the population in the 2017.
Solution :- Let the population in the year 2017 be 100
Therefore, 2018 population = 100 + 10 = 110
Now we will do cross multiplication
105 x = 118800 x 100
x = 118800 x 100
110
= 1,08,000
Ans. The population of the city in the year 2017 is 1,08,000.
Profit and Loss
First, for finding the profit and loss, we need to learn this definitions.
►Cost Price- It is the price at which an article is purchased. It is denoted by CP.
►Selling Price- It is the price at which an article is sold. It is denoted by SP.
Now, we are ready for learning what is Profit.
►Profit- If the Selling Price (SP) is more than the Cost price (CP), then the seller earns a gain or a profit.
Now, we are ready for learning what is Loss.
►Loss- If the Cost Price (CP) is more than the Selling price (SP), then the seller suffers a loss.
Profit and Loss Sums
Before, we start solving the sums, we have to learn the formulas which are useful in these types of sums.
Profit % = Profit x 100
CP
Loss % = Loss x 100
CP
SP = 100+Profit
CP 100
SP = 100-Loss
CP 100
Marketed Price and Discount
In every shops, every article which is to be sold has a price written on it. This price which is tagged to it or marked on it is called the marked price. It is denoted by MP.
Discount is always expressed as a percent of the marked price.
Sales Price - Market Price Relationship
Sale Price = MP - Discount
Discount % = Discount x 100
MP
Goods and Service Tax (GST)
Goods and Service Tax (GST) is a destination based tax on comsumption of goods and service. It has replaced sales tax and VAT.
Simple Interset
In Simple Interset, the interset on a given amount remains the same every year. In other words, the depositor will earn the same amount of interest every year during the money deposit period.
Simple Interest = P x R x T
100
Where P is Principal, R is Rate and T is Time.
To calculate percentage of increase and decrease we need to use this formulas
Increase % = Actual increase x 100
Original
Decrease % = Actual decrease x 100
Original
Example 1. The price of a tablet was ₹22,000 last year. If there is a decrease of 10 %. What is the price of the tablet this year ?
Solution : Price of tablet last year = ₹22,000
Actual decrease = 10 % of ₹22,000
= ₹ 10 x 22,000
100
= ₹2,200
Price of the tablet this year = ₹(22,000 - 2200) = ₹19,800
Example 2. The population of city increases every year by 10 %. If the Population in the year 2018 is 1,18,800. What was the population in the 2017.
Solution :- Let the population in the year 2017 be 100
Therefore, 2018 population = 100 + 10 = 110
| Population | in 2018 | 2017 |
| Assumed | 110 | 100 |
| Actual | 118800 | x |
Now we will do cross multiplication
105 x = 118800 x 100
x = 118800 x 100
110
= 1,08,000
Ans. The population of the city in the year 2017 is 1,08,000.
Profit and Loss
First, for finding the profit and loss, we need to learn this definitions.
►Cost Price- It is the price at which an article is purchased. It is denoted by CP.
►Selling Price- It is the price at which an article is sold. It is denoted by SP.
Now, we are ready for learning what is Profit.
►Profit- If the Selling Price (SP) is more than the Cost price (CP), then the seller earns a gain or a profit.
Now, we are ready for learning what is Loss.
►Loss- If the Cost Price (CP) is more than the Selling price (SP), then the seller suffers a loss.
Profit and Loss Sums
Before, we start solving the sums, we have to learn the formulas which are useful in these types of sums.
Profit % = Profit x 100
CP
Loss % = Loss x 100
CP
SP = 100+Profit
CP 100
SP = 100-Loss
CP 100
Marketed Price and Discount
In every shops, every article which is to be sold has a price written on it. This price which is tagged to it or marked on it is called the marked price. It is denoted by MP.
Discount is always expressed as a percent of the marked price.
Sales Price - Market Price Relationship
Sale Price = MP - Discount
Discount % = Discount x 100
MP
Goods and Service Tax (GST)
Goods and Service Tax (GST) is a destination based tax on comsumption of goods and service. It has replaced sales tax and VAT.
Simple Interset
In Simple Interset, the interset on a given amount remains the same every year. In other words, the depositor will earn the same amount of interest every year during the money deposit period.
Simple Interest = P x R x T
100
Where P is Principal, R is Rate and T is Time.