Quantitative Aptitude Practice Question and Answer

Q: A box contains 5 green, 4 yellow and 5 white pearls. Four pearls are drawn at random. What is the probability that they are not of the same colour ? 2007 0

  • 1
    11/91
    Correct
    Wrong
  • 2
    4/11
    Correct
    Wrong
  • 3
    1/11
    Correct
    Wrong
  • 4
    90/91
    Correct
    Wrong
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Answer : 4. "90/91"
Explanation :

Answer: D) Option D Explanation: Let S be the sample space. Then,n(s) = number of ways of drawing 4 pearls out of 14 = C414 ways = 14×13×12×114×3×2×1= 1001 Let E be the event of drawing 4 pearls of the same colour.Then, E = event of drawing (4 pearls out of 5) or (4 pearls out of 4) or (4 pearls out of 5)   ⇒C15+ C44+ C15 = 5+1+5 =11  P(E) = n(E)n(S)=111001=191      Required probability = 1-191=9091

Q: The first 8 alphabets are written down at random. what is the probability that the letters b,c,d,e always come together ? 1997 0

  • 1
    1/7
    Correct
    Wrong
  • 2
    8!
    Correct
    Wrong
  • 3
    7!
    Correct
    Wrong
  • 4
    1/14
    Correct
    Wrong
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Answer : 4. "1/14"
Explanation :

Answer: D) 1/14 Explanation: The 8 letters can be written in 8! ways.n(S) = 8!Let E be the event that the letters b,c,d,e always come together when the first 8 alphabets are written down.Now the letters a, (bcde), f, g and h can be arranged in 5! ways.The letters b,c,d and e can be arranged themselves in 4! ways.n(E) = 5! x 4!Now, the required P(E) = n(E)/n(S) = 5! x 4!/8! = 1/14Hence the answer is 1/14.

Q: The top and bottom of a tower were seen to be at angles of depression 30° and 60° from the top of a hill of height 100 m. Find the height of the tower ? 1996 1

  • 1
    42.2 mts
    Correct
    Wrong
  • 2
    33.45 mts
    Correct
    Wrong
  • 3
    66.6 mts
    Correct
    Wrong
  • 4
    58.78 mts
    Correct
    Wrong
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Answer : 3. "66.6 mts"
Explanation :

Answer: C) 66.6 mts Explanation: From above diagramAC represents the hill and DE represents the tower Given that AC = 100 m angleXAD = angleADB = 30° (∵ AX || BD ) angleXAE = angleAEC = 60° (∵ AX || CE) Let DE = h Then, BC = DE = h, AB = (100-h) (∵ AC=100 and BC = h), BD = CE tan 60°=AC/CE => √3 = 100/CE =>CE = 100/√3 ----- (1) tan 30° = AB/BD => 1/√3 = 100−h/BD => BD = 100−h(√3)∵ BD = CE and Substitute the value of CE from equation 1 100/√3 = 100−h(√3) => h = 66.66 mts The height of the tower = 66.66 mts.

Q: If the sum of two numbers is 55 and the H.C.F. and L.C.M. of these numbers are 5 and 120 respectively, then the sum of the reciprocals of the numbers is equal to ? 1996 0

  • 1
    13/125
    Correct
    Wrong
  • 2
    14/57
    Correct
    Wrong
  • 3
    11/120
    Correct
    Wrong
  • 4
    16/41
    Correct
    Wrong
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Answer : 3. "11/120"
Explanation :

Answer: C) 11/120 Explanation: Let the numbers be a and b.We know that product of two numbers = Product of their HCF and LCMThen, a + b = 55 and ab = 5 x 120 = 600.=> The required sum = (1/a) + (1/b) = (a+b)/ab=55/600 = 11/120

Q: A man can row 6 kmph in still water. When the river is running at 1.2 kmph, it takes him 1 hour to row to a place and back. What is the total distance traveled by the man ? 1995 0

  • 1
    4.58 kms
    Correct
    Wrong
  • 2
    6.35 kms
    Correct
    Wrong
  • 3
    5.76 kms
    Correct
    Wrong
  • 4
    5.24 kms
    Correct
    Wrong
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Answer : 3. "5.76 kms"
Explanation :

Answer: C) 5.76 kms Explanation: Speed in still water = 6 kmph Stream speed = 1.2 kmph Down stream  = 7.2 kmph Up Stream = 4.8 kmph x/7.2 + x/4.8 = 1 x = 2.88 Total Distance  = 2.88 x 2 = 5.76 kms

Q: A person says that his son is 5 times as old as his daughter and his wife is 5 times older than his son and he is twice the age of his wife . The sum total of all the ages equals the age of the grand mother who celebrated her 81st birthday today. How old was his son? 1993 0

  • 1
    50 yrs
    Correct
    Wrong
  • 2
    25 yrs
    Correct
    Wrong
  • 3
    72 yrs
    Correct
    Wrong
  • 4
    40 yrs
    Correct
    Wrong
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Answer : 1. "50 yrs"
Explanation :

Answer: A) 50 yrs Explanation: Let the daughter age be 'x'Therefore, Son age = 5x, Mother age = 25x, Person age = 50x. Thus we get, x+5x+25x+50x = 8181x = 81x = 1 Daughter's age = 1, Son's = 5, Mother's = 25, Person's age = 50.

Q: The average age of A and B, 2 years ago was 26. If the age of A, 5 years hence is 40 yrs, and B is 5 years younger to C, then find the difference between the age of A and C? 1991 0

  • 1
    11 yrs
    Correct
    Wrong
  • 2
    9 yrs
    Correct
    Wrong
  • 3
    7 yrs
    Correct
    Wrong
  • 4
    13 yrs
    Correct
    Wrong
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Answer : 2. "9 yrs"
Explanation :

Answer: B) 9 yrs Explanation: Let the present ages of A and B be 'x' and 'y' respectively From the given data,  [(x-2) + (y-2)]/2 = 26 => x+y = 56 But given the age of A, 5 years hence is 40 yrs => present age of A = 40 - 5 = 35 yrs => x = 35 => y = 56 - 35 = 21 => Age of B = 21 yrs Given B is 5 years younger to C, => Age of C = 21 + 5 = 26 yrs => Required Difference between ages of A and C = 35 - 26 = 9 yrs.

Q: How many numbers with distinct digits are possible product of whose digits is 18? 1990 0

  • 1
    12
    Correct
    Wrong
  • 2
    8
    Correct
    Wrong
  • 3
    6
    Correct
    Wrong
  • 4
    4
    Correct
    Wrong
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Answer : 2. "8"
Explanation :

Answer: B) 8 Explanation: Two digit numbers: The two digits can be 2 and 9: Two possibilities 29 and 92.Three-digit numbers: The three digits can be 1, 2 and 9 => 3! Or 6 possibilities.We cannot have three digits as (3, 3, 2) as the digits have to be distinct.We cannot have numbers with 4 digits or more without repeating the digits.So, there are totally 8 numbers.

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