Percentage

JKSSB Junior Engineer (Mechanical) · Mathematics · 96 practice questions with answers and explanations: 49 Easy, 44 Medium, 3 Hard.

Sample questions

Sample Easy question 1

The price of an article is first increased by 20% and then decreased by 40%. What is the net percentage change (decrease)?

  1. 28%
  2. 20%
  3. 30%
  4. 27%
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Answer: A. Net change = (20 − 40 − 20×40/100)% = -28%, i.e. a net decrease of 28%.

Sample Easy question 2

The price of an article is first increased by 25% and then decreased by 40%. What is the net percentage change (decrease)?

  1. 24%
  2. 27%
  3. 25%
  4. 15%
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Answer: C. Net change = (25 − 40 − 25×40/100)% = -25%, i.e. a net decrease of 25%.

Sample Easy question 3

The price of an article is first increased by 30% and then decreased by 20%. What is the net percentage change (increase)?

  1. 6%
  2. 3%
  3. 4%
  4. 10%
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Answer: C. Net change = (30 − 20 − 30×20/100)% = 4%, i.e. a net increase of 4%.

Sample Medium question 4

A's income is Rs. 25,000 more than B's, and B's income is 20% less than C's income of Rs. 75,000. Find A's income as a percentage of C's income.

  1. 115%
  2. 113.3%
  3. 108%
  4. 110%
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Answer: B. B = 75000×0.8 = 60,000. A = 60000+25000 = 85,000. A as % of C = 85000/75000×100 ≈ 113.3%.

Sample Medium question 5

A's salary is 25% more than B's salary. What percentage of A's salary is B's salary?

  1. 82%
  2. 75%
  3. 78%
  4. 80%
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Answer: D. If B = 100, A = 125. B as a percentage of A = 100/125 × 100 = 80%.

Sample Medium question 6

In an examination, a student who scores 40% fails by 20 marks, while the passing mark is 50%. Find the maximum marks.

  1. 180
  2. 220
  3. 190
  4. 200
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Answer: D. Let max marks = M. 0.4M + 20 = 0.5M, so 0.1M = 20, M = 200.

Sample Hard question 7

A trader increases the marked price of goods by 40% above cost, then offers successive discounts of 20% and 10%. Find his net profit percentage.

  1. 0.8%
  2. 1%
  3. 0.5%
  4. 1.2%
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Answer: A. CP=100, MP=140, after 20% discount=112, after 10% discount=100.8, so profit is 0.8%.

Sample Hard question 8

72% of candidates passed in Physics and 68% passed in Chemistry, while 8% failed in both. If 240 candidates passed in both, find the total number of candidates.

  1. 500
  2. 480
  3. 510
  4. 490
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Answer: A. Pass in at least one = 92%. Pass in both% = 72+68-92 = 48%. 48% of total = 240, so total = 500.

Sample Hard question 9

In an election with two candidates, 10% of the votes were declared invalid. The winning candidate got 60% of the valid votes and won by 9,720 votes. Find the total number of votes polled.

  1. 48,000
  2. 44,000
  3. 40,000
  4. 54,000
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Answer: D. Valid votes = 90% of total. Winner's margin = 20% of valid votes = 9720, so valid votes = 48,600. Total votes = 48,600/0.9 = 54,000.

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