CBSE Class 5 Mathematics How Heavy How Light Worksheet Set 04

Question 1. A storage container is 60cm long, 25cm wide and 15cm deep. What is its volume in cubic cms?
Answer: Length of the container = 60 cm
Width of the container = 25 cm
Depth of the container = 15 cm
Volume = Length \(\times\) Width \(\times\) Depth
Volume = \(60 \times 25 \times 15\)
Volume = \(1500 \times 15 = 22500\)
Volume = 22500 cm cubes
In simple words: The volume is found by multiplying the length, width, and depth together.
Exam Tip: Always check that all dimensions are in the same unit (centimetres here) before multiplying.

Question 2. Bindu is going to order some ready - mix concrete for an area 6m long and 5m wide, which needs be laid to a depth of 10cm. How many cubic metres of concrete will she need?
Answer: Length = 6 m
Width = 5 m
Depth = 10 cm = \(\frac{10}{100}\) m = 0.1 m
Volume of concrete required = Length \(\times\) Width \(\times\) Depth
Volume = \(6 \times 5 \times 0.1\)
Volume = \(30 \times 0.1 = 3\)
Volume = 3 cubic metres
In simple words: Convert the depth from centimetres to metres first, then multiply length, width, and depth to get the volume in cubic metres.

Exam Tip: Pay close attention to mixed units in a question. Convert centimetres to metres by dividing by 100.

Question 3. How many litres of water are needed to fill the paddling pool to a depth of 30cm?
Answer: From the accompanying diagram, the dimensions of the paddling pool are length = 4 m, width = 1.5 m, and depth = 30 cm.
Length = 4 m
Width = 1.5 m
Depth = 30 cm = 0.3 m
Volume = Length \(\times\) Width \(\times\) Depth
Volume = \(4 \times 1.5 \times 0.3\)
Volume = \(6 \times 0.3 = 1.8\) cubic metres
Since 1 cubic metre = 1000 litres:
Total water needed = \(1.8 \times 1000 = 1800\) litres
Volume in cm cubes = \(1800000\) cm cubes
In simple words: First find the volume in cubic metres, then multiply by 1000 to convert cubic metres into litres.

Exam Tip: Remember the standard conversion: 1 cubic metre = 1000 litres.

Question 4. Sonia has a rectangular pool in her garden which is 4m by 2m. She has cleaned it out and wants to refill it with water to a depth of 25cm. How many litres of water does she need?
Answer: Length of the pool = 4 m
Width of the pool = 2 m
Depth of the water = 25 cm = \(\frac{25}{100}\) m = 0.25 m
Volume of water = Length \(\times\) Width \(\times\) Depth
Volume = \(4 \times 2 \times 0.25\)
Volume = \(8 \times 0.25 = 2\) cubic metres
Since 1 cubic metre = 1000 litres:
Total water needed = \(2 \times 1000 = 2000\) litres
Volume in cm cubes = \(2000000\) cm cubes
In simple words: Multiply the pool dimensions in metres to get the volume in cubic metres, then convert to litres by multiplying by 1000.

Exam Tip: Always write the final unit clearly as requested by the question (litres or cubic centimetres).