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Air is an Important Inexhaustible Natural Resource. It is Essential for the Survival of Human Beings, Microbes, Plants, and Animals. the Following Table Shows the Percentage of Various

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Question

Air is an important inexhaustible natural resource. It is essential for the survival of human beings, microbes, plants, and animals. The following table shows the percentage of various gases in the air.

Contents of air Percentage (by volume)
Nitrogen 78
Oxygen 21
Other (carbon dioxide, inert gases, water vapours, etc.) 1

If a certain quantity (by volume) of air contains 4,200 litres of oxygen, find the total quantity of air taken and the amount of nitrogen in it.

Sum
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Solution

Nitrogen in air = 78%, Oxygen = 21%, Others = 1%

If the air contains 4200 litres of oxygen, then the total quantity of air

= `(4200xx100)/21` litres

= 200 × 100 litres

= 20000 litres

and the amount of nitrogen in it = 20000 of 78%

= `20000xx78/100`

= 15600 litres

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Chapter 16: Percent (Percentage) - Revision Exercise

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Selina Mathematics [English] Class 6
Chapter 16 Percent (Percentage)
Revision Exercise | Q 15.2

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When you design your healthy diet, you want to make sure that you meet the dietary requirements to help you grow into a healthy adult. As you plan your menu, follow the following guidelines

  1. Calculate your ideal weight as per your height from the table given at the end of this question.
  2. An active child should eat around 55.11 calories for each kilogram desired weight.
  3. 55 per cent of calories should come from carbohydrates. There are 4 calories in each gram of carbohydrates.
  4. 15 per cent of your calories should come from proteins. There are 4 calories in each gram of proteins.
  5. 30 per cent of your calories may come from fats. There are 9 calories in each gram of fat.

Following is an example to design your own healthy diet.

Example

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  3. Calories that should come from carbohydrates = 2204.4 × 0.55 = 1212.42 calories.
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Answer the Given Questions

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  5. The quantity of carbohydrates required is ______ g.
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