Question

If the cost of 7 metres of cloth is Rs 294, find the cost of 5m of cloth.

Answer 1

Hint:
Use a unitary method, first find the cost of 1m of cloth by dividing the cost of 7 metres of cloth by 7 and then to find the cost of 5 meters of cloth multiply the cost of 1m of cloth by 5.

Complete step by step solution:
Here,
Given: cost of 7 metres of cloth is Rs 294;
First of all we should understand the unitary method. So the unitary method is a technique for solving a problem by first finding the value of a single unit, and then finding the necessary value by multiplying the single unit value.
Now as we know what unitary method is, let’s solve the problem.
so, cost of 7m cloth = Rs 294
so, cost of 1m cloth = Rs $\dfrac{{294}}{7}$
          \[42\]
\[7)\overline {294\,\,\,\,\,\,} \]
    \[
  \underline {28\,\,\,\,\,\,\,\,} \\
 \times \, 14 \\
 \]
          \[
   14 \\
    \overline {\,\,0\,\, } \\
 \]
so, cost of 1m cloth = Rs 42
Now, cost of 5m cloth = Rs 42 × 5
Since the cost of 1m cloth is Rs 42 so, in order to get the cost of 5m, simply multiply it by 5.
Cost of 5m cloth = 210

So, the answer is Rs 210.

Note:
In essence, a unitary method is used to find the value of a unit from the value of a multiple, and hence the value of a multiple. In the unitary method we used to get the amount for 1 unit then we multiplied it with the number for which we needed to get the value.