Question

If $30$ metres of cloth can be bought for $Rs810$, how many metres of cloth can be bought for $Rs1215$ ?

Answer 1

Hint: From the given conditions, first calculate the price of $1\,m$ of cloth. Then if we get the price of $1\,m$ of cloth we can easily find how many metres of cloth can be purchased from the given specified amount.

Complete step by step solution:
According to the question we are given,
$30$ metres of cloth can be bought for rupees $=Rs810$
So, firstly we will calculate the price of $1\,m$ of cloth using this condition
$\therefore $ $1\,m$ of cloth can be bought for rupees$=\dfrac{810}{30}=27$
Thus we get the price of $1\,m$ of cloth as $Rs27$
Now, we are asked to find how many metres of cloth can be bought in $Rs1215$
Let us suppose that $x$ metres of cloth can be bought in $Rs.1215$
So price of $1\,m$ of cloth $=Rs27$
$\therefore $ Price of $x$ metres of cloth $=x\times 27$
And cost we are given as $Rs1215$
So, we can equate both the cost of cloth to get the value of $x$ metres of cloth,
$\Rightarrow x\times 27=1215$
$\Rightarrow x=\dfrac{1215}{27}$
$\Rightarrow x=45$

Thus, we can buy $45$ metres of cloth in $Rs1215$.

Note: These types of questions are solved using the unitary method which involves first finding the value of a single unit from the given multiple units, and then finding the necessary units using the value of the single unit. The method is mainly used for finding the price of a good or any other item.