Question

what is unitary method

Answer 1

the unitary method is a technique which is used for solving a problem by finding value of single unit..

Answer 2

$\bf Unitary \: Method :-$

In order to understand the unitary method, let us consider the following problem:

If the cost of 4 pens is Rs 20. What will be the cost of 7 pens?

We may think of the solution of this problem as follows:

The cost of 4 pens is Rs 20. So, the cost of one pen will be lesser than Rs 20. In fact, the cost of one pen will be equal to one part when Rs 20 are divided into 4 equal parts. So, we find the cost of one pen by dividing Rs 20 by 4 and we get the cost of one pen as Rs 5. We have to find the cost of 7 pens.

Clearly, it will be more than the cost of one pen. In fact, it will be 7 times the cost of one pen. So, we multiply Rs 5 by 7 to get the cost of 7 pens as Rs (5 × 7) = Rs 35. In the solution of the above problem, first we have found out the value of one unit (in fact the value of one pen) and than the value of the desired number of units by multiplying the value of one unit with the number of desired units. Such a method of problem solving is called the unitary method

Example:-

The cost of 30 m of polyester cloth is rupees 450 find the cost of 16 m of cloth.

Solution :-

We have,

Cost of 30 metres of cloth = Rs. 450

Cost of 1 metres of cloth = Rs. 450/30

Hence, cost of 16 metres of cloth

$\sf Rs. \bigg ( \dfrac{450}{30} \times 16 \bigg) = Rs.(15 \times 16)$

$\sf \longmapsto Rs. 240$