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. 20

B. 18

C. 15

D. 10

Answer: Option A

Solution (By JKExamLibrary)

(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

A train 150 m long crosses a pole in 10 seconds. What is its speed in kmph?

A. 60 kmph

B. 36 kmph

C. 45 kmph

D. 54 kmph

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Correct Answer: Option D

Explanation:
Speed = 150/10 = 15 m/s = 15 × 18/5 = 54 kmph.

This question belongs to: Maths Percentage

Question #2

Price of petrol increased by 25%. To keep expenditure same, consumption must reduce by:

A. 10%

B. 25%

C. 15%

D. 20%

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Correct Answer: Option D

Explanation:
Reduction % = (25/125)×100 = 20%.

This question belongs to: Maths Percentage

Question #3

A's income is 25% more than B's. B's expenditure is 40% less than A's. If A saves 20% of his income, what percent does B save?

A. 30%

B. 45%

C. 40%

D. 35%

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Correct Answer: Option C

Explanation:
Let B inc=100, A=125. A sav=25, A exp=100. B exp=0.6×100=60, B sav=100-60=40, i.e. 40%.

This question belongs to: Maths Percentage

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