Page 149 - Maths Class 05

9 The Unitary Method

The word unitary refers to a single or an individual unit. Hence, this method aims at
determining values in relation to a single unit. For example, if a car runs 44 km in 2 litres of

petrol then we can use the unitary method to find out the kilometres it will cover in 1 litre of
petrol.

In other words, the method by which we find out the value of one unit and further use it to
find the value of multiple units is known as the unitary method. Let us understand the

application of unitary method by an example.

Suppose Ram buys a dozen (12) bananas for ` 36. The cost of 12 bananas = ` 36. The cost
of 1 banana = ` 36 ÷ 12 = ` 3. Hence, a single banana costs 3 rupees. Now, suppose we

need to find the cost of 15 bananas. This can be done as :
The cost of 15 bananas = ` 3 × 15 units = ` 45.

In essence, if the value of multiple items is given to us, we simply divide the total value by

the number of units to obtain the value of one unit. This is the unitary method.
Profit and Loss

Mr Jain is a wholesale dealer of pens. He buys pens from the factory and sells them in

his shop. He bought pens for ` 220 per box and sold the same for ` 245 per box.
Naturally he has earned some money in the whole transaction.

He has earned ` 245 – ` 220 = ` 25
` 220 is called the cost price (C.P.) of the pens.

` 245 is called the selling price (S. P.) of the pens.

` 25 is the profit earned by Mr Jain.

H The price at which an item is bought is called cost price .

H The price at which an item is sold is called selling price .
H When selling price is more than the cost price, there is a profit .

Profit = S. P. – C. P.

What will happen if Mr Jain had to sell the pens for an amount less than the cost price ?

Suppose Mr Jain had to sell the pens for ` 195 per box.
Here selling price is less than the cost price. Mr Jain would have to bear a loss.

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