Question

Due to pulse polio campaign,the number of polio cases in uttrakhand has come down by 85% to 135.Find the number of cases earlier

Answer 1

let the number of polio cases earlier be'x'

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Find the decrease:
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decrease in cases = 85 %

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= 85% of x = 0.85x

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cases remaining:
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remaining cases=total cases-decrease

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= x - 0.85x = x ( 1 - 0.85 ) = 0.15x

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so according to question,

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remaining cases = 135

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0.15x = 135

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15x ÷ 100 = 135 => 15x = 13500

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x = 13500 ÷ 15 => x = 900 cases

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Answer:
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the number of cases earlier was 900.

Answer 2

please refer to the above attachment mate