The internal measures of a cuboidal room are `12m xx 8m xx 4m` . Find the total cost of whitewashing all four walls of a room, if the cost of white washing is Rs 5 per `m^2`. What will be the cost of white washing if the ceiling of the room is also whitewashed.

Explanation

To solve the problem step by step, we will first calculate the area of the four walls of the cuboidal room and then find the cost of whitewashing those walls. After that, we will calculate the cost if the ceiling is also whitewashed.

### Step 1: Calculate the area of the four walls of the cuboidal room.

The formula for the total surface area of the four walls of a cuboid is given by:
\[ \text{Area of walls} = 2 \times (l + b) \times h \]
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