Math Problem Statement

Isabella is going to paint the 4 walls and the ceiling of a room in the shape of a cuboid with dimensions: 2.8 m (length), 2.0 m (width), and 2.2 m (height). Paint is sold in tins, each costing £49.99 and covering 3 m². Calculate the cost of the paint needed to paint the 4 walls and the ceiling.

Solution

Problem Analysis:

  1. Shape of the room: The room is a cuboid with dimensions:

    • Length: 2.8m2.8 \, \text{m}
    • Width: 2.0m2.0 \, \text{m}
    • Height: 2.2m2.2 \, \text{m}
  2. Areas to be painted:

    • The 4 walls and the ceiling.
  3. Paint details:

    • Cost of a tin of paint: £49.99
    • Coverage per tin: 3m23 \, \text{m}^2

Step-by-Step Solution:

Step 1: Calculate the surface area of the walls

The room has four walls, which include:

  • Two walls of dimensions 2.8m×2.2m2.8 \, \text{m} \times 2.2 \, \text{m}
  • Two walls of dimensions 2.0m×2.2m2.0 \, \text{m} \times 2.2 \, \text{m}

The total area of the walls is: 2×(2.8×2.2)+2×(2.0×2.2)2 \times (2.8 \times 2.2) + 2 \times (2.0 \times 2.2)

=2×6.16+2×4.4=12.32+8.8=21.12m2= 2 \times 6.16 + 2 \times 4.4 = 12.32 + 8.8 = 21.12 \, \text{m}^2


Step 2: Calculate the surface area of the ceiling

The ceiling has dimensions 2.8m×2.0m2.8 \, \text{m} \times 2.0 \, \text{m}. Its area is: 2.8×2.0=5.6m22.8 \times 2.0 = 5.6 \, \text{m}^2


Step 3: Total surface area to paint

The total area is: 21.12+5.6=26.72m221.12 + 5.6 = 26.72 \, \text{m}^2


Step 4: Calculate the number of tins of paint needed

Each tin covers 3m23 \, \text{m}^2. The number of tins required is: 26.723=8.9067=9tins\lceil \frac{26.72}{3} \rceil = \lceil 8.9067 \rceil = 9 \, \text{tins}


Step 5: Calculate the total cost

The cost of one tin is £49.99. The total cost is: 9×49.99=449.91GBP9 \times 49.99 = 449.91 \, \text{GBP}


Final Answer:

The total cost of the paint needed to paint the 4 walls and the ceiling is £449.91.


Do you need further explanation or details?

Related Questions:

  1. How would the cost change if each tin covered 4m24 \, \text{m}^2?
  2. What would be the cost for painting only the walls, excluding the ceiling?
  3. If the room height was reduced to 2.0m2.0 \, \text{m}, how many tins would be required?
  4. How can you minimize leftover paint in this situation?
  5. Can you calculate the cost of painting two such rooms?

Tip:

Always round up when calculating the number of tins needed, as partial tins cannot be purchased.

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Math Problem Analysis

Mathematical Concepts

Geometry
Surface Area
Rounding
Unit Conversion

Formulas

Area of a rectangle = length × width
Total area to paint = Area of 4 walls + Area of ceiling
Number of tins required = ceil(Total area / Coverage per tin)

Theorems

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Suitable Grade Level

Grades 6-8