A number is increased by x% and then decreased by x%. The net decrease is 4%. Find x. MCQ with Answer and Explanation

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A number is increased by x% and then decreased by x%. The net decrease is 4%. Find x.

A. 10

B. 20

C. 15

D. 18

Answer: Option B

Solution (By JKSSB Mock Tests)

(1 + x/100)(1 - x/100) = 1 - (x²/10000) = 0.96 → x² = 400 → x = 20.

This question belongs to: Maths Percentage

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Practice More Percentage Questions

Question #1

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If the cost price of 12 articles is equal to the selling price of 10 articles, what is the profit percent?

A. 25%

B. 20%

C. 18%

D. 15%

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Correct Answer: Option B

Explanation:
Let CP of 1 article = Re.1. CP of 12 = 12, SP of 10 = 12 → SP of 1 = 1.2, profit% = 20%.

This question belongs to: Maths Percentage

Question #2

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A train 250 m long passes a man running at 5 kmph in the same direction in which the train is going, in 10 seconds. Find the speed of the train.

A. 90 kmph

B. 85 kmph

C. 80 kmph

D. 95 kmph

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Correct Answer: Option D

Explanation:
Relative speed = (250/10) m/s = 25 m/s = 90 kmph. Speed of train = relative speed + man's speed = 90 + 5 = 95 kmph. (Man running same direction, so train overtakes, relative speed = train speed - man speed). So train speed = 25 m/s + 5 kmph? 25 m/s = 90 kmph, man 5 kmph, so train 95 kmph. Yes.

This question belongs to: Maths Percentage