Answer:

1. Area of tank PAINTED by WHITE colour = 36 m²
2. Area of cover of tank painted by blue colour = 20 m²
3. Tank can hold 40000 L of water.

Step-by-step explanation:

Given that:

Dimensions of cuboidal water tank:

• Length = 5 m
• Breadth = 4 m
• HEIGHT = 2 m

• He also decided to make a iron cover for the tank.
• He used white colour to paint the four walls of the tank.
• Blue colour to paint the cover of the tank.

To FIND:

1. Area of tank painted by white colour.
2. Area of cover of tank painted by blue colour.
3. How much volume of water can be tank hold?

Formula used:

1. C.S.A. = 2H(L + B)
2. A = (L × B)
3. V = (L × B × H)

Where,

• C.S.A. = Curved surface area of a cuboid
• A = Area of top of a cuboid
• V = Volume of a cuboid
• L = Length of a cuboid
• B = Breadth of a cuboid
• H = Height of a cuboid

Finding the area of tank painted by white colour:

⇒ C.S.A. = 2 × 2(5 + 4)

⇒ C.S.A. = 4(9)

⇒ C.S.A. = 36

∴ Area of tank painted by white colour = 36 m²

Finding the area of cover of tank painted by blue colour:

⇒ A = (5 × 4)

⇒ A = 20

∴ Area of cover of tank painted by blue colour = 20 m²

Finding the volume of tank:

⇒ V = (5 × 4 × 2)

⇒ V = 40

∴ Volume of water tank = 40 m³

Converting the volume in litres.

∵ 1 m³ = 1000 L

∴ 40 m³ = (40 × 1000) L

∴ 40 m³ = 40000 L

Hence, Water tank can hold 40000 L of water.