Find the cost of whitewashing a wall measuring 21 feet by 10 feet at the rate of ₹ 18 per square foot.

Answer

To find the cost of whitewashing a wall measuring 21 feet by 10 feet at the rate of ₹ 18 per square foot, we can follow these steps:

### Step 1: Calculate the Area of the Wall
The wall is rectangular, so we can calculate the area using the formula:
\[ \text{Area} = \text{Length} \times \text{Breadth} \]
Here, the length is 21 feet and the breadth is 10 feet.

\[ \text{Area} = 21 \, \text{feet} \times 10 \, \text{feet} = 210 \, \text{square feet} \]

### Step 2: Calculate the Cost of Whitewashing
Next, we need to find the cost of whitewashing the wall. The cost is calculated by multiplying the area of the wall by the rate of whitewashing per square foot.

\[ \text{Cost} = \text{Area} \times \text{Rate} \]
Given that the rate is ₹ 18 per square foot, we can substitute the values:

\[ \text{Cost} = 210 \, \text{square feet} \times 18 \, \text{₹/square foot} \]

### Step 3: Perform the Multiplication
Now, we will multiply 210 by 18:

\[ \text{Cost} = 210 \times 18 = 3780 \, \text{₹} \]

### Final Answer
The total cost of whitewashing the wall is ₹ 3780.

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