**Given Information:**
- Dimension of the room: 8m × 6m × 3m
- Cost of painting per square meter: Rs 60

**To Find:**
- Cost of painting the walls of the room

**Solution:**
To calculate the cost of painting the walls of the room, we need to find the area of the walls first.

**Finding the Area of the Walls:**
- The room has six walls: four walls, one ceiling, and one floor.
- We need to find the area of the four walls only, as the ceiling and floor are not to be painted.
- The area of a rectangular wall is given by the formula: length × height.
- The room has two pairs of walls with the same dimensions: the front and back walls, and the left and right walls.
- The area of each pair of walls is the same, so we can calculate the area of one pair and multiply it by 2 to get the total area of the four walls.

**Calculating the Area of the Walls:**
- Front and back walls: length × height = 8m × 3m = 24 square meters
- Left and right walls: length × height = 6m × 3m = 18 square meters
- Total area of the four walls = (24 + 18) × 2 = 84 square meters

**Calculating the Cost of Painting:**
- Cost of painting per square meter = Rs 60
- Total area of the four walls = 84 square meters
- Cost of painting the walls = Cost per square meter × Total area of the four walls
- Cost of painting the walls = Rs 60 × 84 = Rs 5040

**Therefore, the cost of painting the walls of the room is Rs 5040.

We have : L=8m, B=6m, H=3m. rate of painting = Rs 60 per square metre. we know that, Lateral surface area of room = 2×(L+B)×H. = 2×(8+6)×3 m. = 2×14×3 m. = 84 m. Total cost of painting = Area × rate of painting. = Rs 84×60. = Rs 5040.