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Increase Or Decrease as Percent

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Increase or Decrease as a percent:

The increase or decrease in a certain quantity can also be expressed as a percentage.

There are times when we need to know the increase or decrease in a certain quantity as a percentage.

For example, if the population of a state increased from 5,50,000 to 6,05,000. Then the increase in population can be understood better if we say, the population increased by 10 %.

Example

A school team won 6 games this year against 4 games won last year. What is the percent increase

The increase in the number of wins (or amount of change) = 6 – 4 = 2.

Percentage increase = `"Amount of change"/"Original amount or base" xx 100`

= `"Increase in the number of wins"/"Original amount of wins" xx 100`

= `2/4 xx 100 = 50`.

Example

The number of illiterate persons in a country decreased from 150 lakhs to 100 lakhs in 10 years. What is the percentage of decrease?

Original amount = the number of illiterate persons initially = 150 lakhs.
Amount of change = decrease in the number of illiterate persons = 150 – 100 = 50 lakhs.
Therefore, the percentage of decrease = `"Amount of change"/"Original amount" xx 100`

= `(550)/(150) × 100`

= `33 1/3`.

Example

The price of a scooter was Rs. 34,000 last year. It has increased by 20% this year. What is the price now?
The increase in the price, which is 20% of Rs. 34,000.
20% of Rs. 34000 = Rs. `20/100 xx 34000` = Rs. 6800
New price = Old price + Increase
= Rs. 34,000 + Rs. 6,800
= Rs. 40,800.

20% increase means, Rs. 100 increased to Rs. 120.
So, Rs. 34,000 will increase to?

Increased price = Rs. `120/100 xx 34000` = 40,800.

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