Quantitative Aptitude Practice Question and Answer

Q: The mean of 100 observations is 40. It is found that an observation 84 was misread as 48. Then the correct mean is ? 1814 0

  • 1
    40.36
    Correct
    Wrong
  • 2
    41.24
    Correct
    Wrong
  • 3
    41.92
    Correct
    Wrong
  • 4
    42.05
    Correct
    Wrong
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Answer : 1. "40.36"
Explanation :

Answer: A) 40.36 Explanation: Given, mean of 100 observations is 40 => Total of 100 observations = 40 x 100 = 4000 84 is misread as 48 => Difference = 84 - 48 = 36 => Now, new total of 100 observations = 4000 + 36 = 4036 Correct Mean = 4036/100 = 40.36

Q: A room contains 3 brown, 5 black and 4 white chairs. Two chairs are picked and are put in the lawn. What is the probability that none of the chairs picked is white ? 1814 0

  • 1
    14/33
    Correct
    Wrong
  • 2
    14/55
    Correct
    Wrong
  • 3
    12/55
    Correct
    Wrong
  • 4
    13/33
    Correct
    Wrong
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Answer : 1. "14/33"
Explanation :

Answer: A) 14/33 Explanation: Total number of chairs = (3 + 5 + 4) = 12. Let S be the sample space. Then, n(s)= Number of ways of picking 2 chairs out of 12 = 12×11/2×1 = 66 Let n(E) = number of events of selecting 2 chairs for selecting no white chairs. => 8C2 = 8×7/2×1 = 28 Therefore required probability = 28/66 = 14/33.

Q: The sum of the digits of a two-digit number is 12. The difference of the digits is 6. Find the number ? 1813 0

  • 1
    57
    Correct
    Wrong
  • 2
    75
    Correct
    Wrong
  • 3
    48
    Correct
    Wrong
  • 4
    39
    Correct
    Wrong
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Answer : 4. "39"
Explanation :

Answer: D) 39 Explanation: Let the two-digit number be 10a + ba + b = 12 --- (1)If a>b, a - b = 6If b>a, b - a = 6If a - b = 6, adding it to equation (1), we get2a = 18 => a =9so b = 12 - a = 3Number would be 93.if b - a = 6, adding it to the equation (1), we get2b = 18 => b = 9a = 12 - b = 3.Number would be 39.There fore, Number would be 39 or 93.

Q: In a bag, there are 8 red, 7 blue and 6 green flowers. One of the flower is picked up randomly. What is the probability that it is neither red nor green ? 1812 0

  • 1
    13
    Correct
    Wrong
  • 2
    821
    Correct
    Wrong
  • 3
    621
    Correct
    Wrong
  • 4
    2021
    Correct
    Wrong
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Answer : 1. "13"
Explanation :

Answer: A) Option A Explanation: Total number of flowers = (8+7+6) = 21.   Let E = event that the flower drawn is neither red nor green.  = event taht the flower drawn is blue.    --> n(E)= 7  --> P(E)=  721=13

Q: How many 4-letter words with or without meaning, can be formed out of the letters of the word, 'LOGARITHMS', if repetition of letters is not allowed ? 1812 0

  • 1
    5040
    Correct
    Wrong
  • 2
    2525
    Correct
    Wrong
  • 3
    2052
    Correct
    Wrong
  • 4
    4521
    Correct
    Wrong
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Answer : 1. "5040"
Explanation :

Answer: A) 5040 Explanation: The Word LOGARITHMS  contains 10 letters. To find how many 4 letter words we can form from that = P410 =10x9x8x7 = 5040.

Q: 74.99% of 1299 + 8.98% of 1899 = ? 1811 0

  • 1
    1378
    Correct
    Wrong
  • 2
    1301
    Correct
    Wrong
  • 3
    1212
    Correct
    Wrong
  • 4
    1197
    Correct
    Wrong
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Answer : 3. "1212"
Explanation :

Answer: C) 1212 Explanation: 74.99% of 1299 + 8.98% of 1899 = ?  ? = 75 x 1400100 + 9 x 1800100 ? = 1050 + 162? = 1212.

Q: Calender Puzzle 1811 0

  • 1
    A
    Correct
    Wrong
  • 2
    B
    Correct
    Wrong
  • 3
    C
    Correct
    Wrong
  • 4
    D
    Correct
    Wrong
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Answer : 4. "D"
Explanation :

Answer: D) D Explanation: We can't determine the last day of the next month which has 31 days because we don't know the days in present month which may be 30 or 31. And the next month may be March which contains 31 days  which implies that the present month may be February which contains 28 or 29 days.

Q: Out of seven consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed ? 1810 0

  • 1
    25200
    Correct
    Wrong
  • 2
    25000
    Correct
    Wrong
  • 3
    25225
    Correct
    Wrong
  • 4
    24752
    Correct
    Wrong
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Answer : 1. "25200"
Explanation :

Answer: A) 25200 Explanation: Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4) =( C37×C24 ) = 210. Number of groups, each having 3 consonants and 2 vowels =210 Each group contains 5 letters. Number of ways of arranging 5 letters among themselves = 5! = 120.  Required number of words = (210 x 120) = 25200.

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