Question

How many paving stones each measuring 1 m by 90 cm are required to pave a rectangular verandah 60
metres by 3 metres?
​

Answer 1

Answer: 200 Paving stones

We have the measurement of the paving stones and the rectangular verandah as given in the question :-

• Paving stone = 1 m × 90 cm
• Verandah = 60 m × 3 m

Before moving further, Let's make the units same of both the measurements. as we can see the measurement of stone is in m by cm so let's make it m by m by dividing the cm measure with 100.

As, 1 m = 100 cm

So, The measurement of paving stone in m by m will be:

• Paving stone = 1 m × 0.9 m

Because, The paving stones is going to be fit on the surface of the verandah, Hence the surface area of stone will cover the same surface area of the rectangular verandah.

Hence, We can find the number of paving stones by dividing the surface area of the verandah by surface area of the paving stone.

Since, Both are in rectangular shape, so the area of them can be found by the formula,

• Surface Area = Length × Breadth

Surface Area of Stone:-

• Length = 1 m
• Breadth = 0.9 m

Then,

⇒ Surface Area = Length × Breadth

⇒ Surface Area = 1 × 0.9

⇒ Surface Area = 0.9 m²

Surface Area of Verandah:-

• Length = 60 m
• Breadth = 3 m

Then,

⇒ Surface Area = Length × Breadth

⇒ Surface Area = 60 × 3

⇒ Surface Area = 180 m²

As discussed earlier,

⇒ No. of stone = SA of verandah / SA of stone

[ Here, Surface Area is abbreviated as SA ]

⇒ No. of stone = 180 / 0.9

Because, Denominator is in decimal, Multiply & Divide by such a number that both numerator and denominator becomes a real number (This is for simplicity, You can still divide it).

Dividing and Multiplying by 10, we get

⇒ No. of stone = 1800 / 9

⇒ No. of stone = 200

Hence, 200 paving stones are required for the pavement of the rectangular verandah.

Answer 2

Given :-

Dimensions of stone = 1 m by 90 cm

Length of verandah = 60 m by 3 m

To Find :-

Total stone required

Solution :-

We know that

Area = Length × Breadth

And 1 m = 100 cm

So,

Length of stone = 1 × 100 = 100 cm

Area = 100 × 90

Area = 9000 cm²

60 m = 60 × 100 = 6000 cm

3 m = 3 × 100 = 300 cm

Area of verandah = 6000 × 300

Area = 1800000 cm²

No. of stone required = 1800000/9000

No. of stone required = 1800/9

No. of stone required = 200