A tank is in the shape of a rectangular parallelepiped of size 50 m × 40 m × 3 m. Its capacity in kilolitres is

Correct — A. Capacity is the volume of the cuboid, converted to kilolitres.

Volume = length × breadth × height = 50 × 40 × 3
= 2,000 × 3 = 6,000 m³

Convert: 1 m³ = 1,000 litres = 1 kilolitre
6,000 m³ = 6,000 kilolitres → option (a)

Why the others are wrong

• (b)
  5,000 kilolitres — 5,000 kL is 5,000 m³, which needs a depth of 5,000 ÷ 2,000 = 2.5 m. The tank is 3 m deep.
• (c)
  4,500 kilolitres — 4,500 kL is 50 × 30 × 3, a tank 30 m wide. The width is 40 m, so the floor is 2,000 m², not 1,500 m².
• (d)
  5,500 kilolitres — 5,500 kL would need a depth of 5,500 ÷ 2,000 = 2.75 m. At the full 3 m depth the volume is 6,000 m³.

A rectangular parallelepiped is a cuboid, a box whose six faces are rectangles, so its volume is length × breadth × height.

The unit bridge does the rest: 1 m³ holds 1,000 litres, and 1,000 litres is 1 kilolitre. So the number of cubic metres equals the number of kilolitres, with no conversion arithmetic at all.

Key facts

• 1 m³ = 1,000 litres = 1 kilolitre.
• 1 litre = 1,000 cm³.
• Volume of a cuboid = length × breadth × height.

Common traps

• Dividing by 1,000 again after finding 6,000 m³, as if cubic metres still needed converting to kilolitres
• Confusing 1 litre = 1,000 cm³ with 1 m³ = 1,000 litres

No directly related past PYQ was found.