Question

The cost of 5 metres of a particular quality of cloth is Rs. 210. Find the cost of 13 metres of cloth of the same quality.

Answer 1

Hint:
First, we will find the cost of one metre of cloth by dividing the cost of 5 metre of cloth by 5. Then multiply the cost of one metre cloth by 13 to find the cost of 13 metre of cloth.

Complete step by step solution:
We are given that the cost of 5 m of cloth is Rs. 210.
First , we will find the cost of one metre of cloth by dividing the total amount of 5 metre cloth by the total quantity of cloth that is by 5 metre.
Hence, cost of one metre of cloth is calculated as, $\dfrac{{{\text{total amount}}}}{{{\text{total quantity}}}}$
Substituting the value 5 for total quantity of cloth and 210 for the total amount of cloth in the expression $\dfrac{{{\text{total amount}}}}{{{\text{total quantity}}}}$, we get
$\dfrac{{210}}{5}$
On simplifying, we get $Rs.42$.
Therefore, the cost of one metre of cloth is Rs. 42.
We can calculate the cost of 13 metre of cloth by multiplying the cost of one metre of cloth by 13.

Therefore, the cost of 13 metre cloth is,
$13\left( {42} \right) = Rs.546$

Note:
In these types of questions, we first find the amount of one item by dividing the total cost by the total number of articles. Then multiply the cost of one item by the number of items whose price we want to calculate. This is known as the unitary method.