हिंदी

The population of a town was decreasing every year due to migration, poverty and unemployment. The present population of the town is 6,31,680. Last year the migration was 4% - Mathematics

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प्रश्न

The population of a town was decreasing every year due to migration, poverty and unemployment. The present population of the town is 6,31,680. Last year the migration was 4% and the year before last, it was 6%. What was the population two years ago?

योग
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उत्तर

Let the population two years ago = P (Principal)

Present population of the town = A = 631680

Rate of migration in 1st year = 4%

Rate of migration in 2nd year = 6%

By using the formula,

`A = P(1 - R/100)(1 - R/100)`

⇒ `631680 = P(1 - 4/100)(1 - 6/100)`

⇒ `631680 = P xx 24/25 xx 47/50`

⇒ `P = (631680 xx 25 xx 50)/(24 xx 47)`

⇒ P = 560 × 1250 = 700000

Hence, the population of town was 700000 two years ago.

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अध्याय 9: Comparing Quantities - Exercise [पृष्ठ २९७]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 8
अध्याय 9 Comparing Quantities
Exercise | Q 91. | पृष्ठ २९७

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