A godown is 50 m long, 40 m broad and 10 m high. Find the cost of whitewashing its four walls and ceiling at Rs.20 per square metre.

Answer

To solve the problem of finding the cost of whitewashing the four walls and ceiling of a godown, we will follow these steps:

### Step 1: Calculate the area of the four walls
The formula to calculate the area of the four walls of a rectangular room is:
\[ \text{Area of four walls} = 2 \times \text{Height} \times (\text{Length} + \text{Breadth}) \]

Given:
- Length = 50 m
- Breadth = 40 m
- Height = 10 m

Substituting the values:
\[ \text{Area of four walls} = 2 \times 10 \times (50 + 40) = 2 \times 10 \times 90 = 1800 \, \text{m}^2 \]

### Step 2: Calculate the area of the ceiling
The area of the ceiling can be calculated using the formula:
\[ \text{Area of ceiling} = \text{Length} \times \text{Breadth} \]

Substituting the values:
\[ \text{Area of ceiling} = 50 \times 40 = 2000 \, \text{m}^2 \]

### Step 3: Calculate the total area to be whitewashed
Now, we will add the area of the four walls and the area of the ceiling to get the total area that needs to be whitewashed:
\[ \text{Total area} = \text{Area of four walls} + \text{Area of ceiling} \]
\[ \text{Total area} = 1800 + 2000 = 3800 \, \text{m}^2 \]

### Step 4: Calculate the cost of whitewashing
The cost of whitewashing is given as Rs. 20 per square meter. Therefore, the total cost can be calculated as:
\[ \text{Total cost} = \text{Total area} \times \text{Cost per square meter} \]
\[ \text{Total cost} = 3800 \times 20 = 76000 \, \text{Rs.} \]

### Final Answer
The total cost of whitewashing the four walls and ceiling of the godown is Rs. 76,000.

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