Proportional Reasoning - 2 | IT

Question 3

Convert 60,00,000 cm60,00,000 \text{ cm} to kilometres.

It is 60 km60 \text{ km}. Verify this.

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Solution
Understand the Question
  • To convert a smaller unit of length into a larger unit, we divide:
    • 1 m=100 cm    1 cm=1100 m1 \text{ m} = 100 \text{ cm} \implies 1 \text{ cm} = \dfrac{1}{100} \text{ m}
    • 1 km=1000 m    1 m=11000 km1 \text{ km} = 1000 \text{ m} \implies 1 \text{ m} = \dfrac{1}{1000} \text{ km}
  • We can first convert centimetres to metres by dividing by 100100, and then convert metres to kilometres by dividing by 10001000.

Step 1 · Convert Centimetres to Metres

Since 1 m=100 cm1 \text{ m} = 100 \text{ cm}:Diagram 1

60,00,000 cm=60,00,000100 m=60,000 m\begin{aligned} 60,00,000 \text{ cm} &= \dfrac{60,00,000}{100} \text{ m} \\[0.6em] &= 60,000 \text{ m} \end{aligned}

Step 2 · Convert Metres to Kilometres

Since 1 km=1000 m1 \text{ km} = 1000 \text{ m}:

60,000 m=60,0001000 km=60 km\begin{aligned} 60,000 \text{ m} &= \dfrac{60,000}{1000} \text{ km} \\[0.6em] &= 60 \text{ km} \end{aligned}

Hence, 60,00,000 cm=60 km60,00,000 \text{ cm} = 60 \text{ km} is verified.

Answer

60 km60 \text{ km} (Verified)

Common Mistakes
  • Operation Error: Multiplying by 100100 and 10001000 instead of dividing when converting from a smaller unit (cm\text{cm}) to a larger unit (km\text{km}).
  • Counting Zeros: Forgetting that 1 km=100,000 cm1 \text{ km} = 100,000 \text{ cm} (55 zeros total), leading to incorrect decimal point placement.

More questions in IT

Q1

Viswanath made idlis by mixing 6 cups of rice with 3 cups of urad dal, while Puneet made idlis by mixing 4 cups of rice with 2 cups of urad dal. If cooked in the same way, would their idlis taste the same?

Q2

Have you noticed that in many maps there is a ratio given, usually in the lower right corner of the map? It usually contains 11 and a very large number, such as 1:60,00,0001 : 60,00,000. What does RF 1:60,00,000\text{RF } 1 : 60,00,000 mean? What does it indicate? Can you guess?

Q3

Convert 60,00,000 cm60,00,000 \text{ cm} to kilometres.

It is 60 km60 \text{ km}. Verify this.

Q4

Using the map above, can you find the geographical distance between Bengaluru and Chennai? Also, find the geographical distance between Mangaluru and Chennai.

[Hint: Use a ruler to find the distance between the cities on the map. Then, use the ratio given on the map to find the actual geographical distance.]

Q5

Try to find the distances between the same two pairs of cities with different maps that have different scales (ratios). Do they all give the same geographical distance, approximately?

Q6

Context: Puneeth's father went from Lucknow to Kanpur in 3 hours by riding his motorcycle at a speed of 30 km/h. If he takes a car instead and drives at 60 km/h, how long will it take him to reach Kanpur?

Q. Can we represent this problem with the following statement of proportionality — 30:60::3:x30 : 60 :: 3 : x? Will the travel time increase or decrease as the speed of the motorcycle increases?

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