Page 134 - Start Up Mathematics_7

Increase or Decrease as Percent
Increase or decrease in a quantity is found as a percentage of the initial or original amount.
Increase
(i) Percentage increase = × 100
Original quantity
Decrease
(ii) Percentage decrease = × 100
Original quantity
Example 17: Saraswat scored 65 marks in his first exam. In the next he scored 80. What is the
percentage increase?
Solution: Increase in marks = 80 – 65 = 15
Increase in marks 15 1
Percentage increase = Original marks × 100 = 65 × 100 = 23 %
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Example 18: Simran bought a car for ` 3,50,000. In the very next year, she sold it for ` 3,00,000.
What is the percentage decrease?
Solution: Initial price of the car = ` 3,50,000
Selling price of the car = ` 3,00,000

Loss = ` 3,50,000 – ` 3,00,000 = ` 50,000
Decrease 50,000 2
Percentage decrease in price = d Initial price n × 100 = 3,50,000 × 100 = 14 %
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Other Applications of Percentage

Profit and Loss
Whenever we buy any product from a shop, we pay some money to the shopkeeper. But do you
know the shopkeeper buys the same product at a relatively cheaper price than what is paid by us.
However, sometimes the shopkeeper may also lose some money in the transaction. Let’s understand
some related terms.
(i) Cost price: The price at which the shopkeeper buys a product is called its cost price (C.P.).
(ii) Selling price: The price at which the shopkeeper sells a product is called selling price
(S.P.).
(iii) Profit: The gain made by the shopkeeper on selling a product is called profit.

(iv) Loss: The money lost on selling a product is termed as loss.
Therefore, we can say if S.P. > C.P., then the transaction results in profit and if C.P. > S.P., then
loss is incurred. Profit or loss percentage is always calculated on the cost price. To find profit, loss
or its percentage, the following formulae are used.
• Profit = S.P. – C.P. • Profit percentage = Profit × 100
C.P.
Loss
• Loss = C.P. – S.P. • Loss percentage = × 100
C.P.
Example 19: Calculate the profit or loss in the following transactions. Also find the profit percent
or loss percent in each case.

(a) A scooter bought for ` 12,000 and sold for ` 10,000.
(b) A laptop bought for ` 25,000 and sold for ` 15,000.

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