GATE Practice Question and Answer

Q: A Committee of 5 persons is to be formed from a group of 6 gentlemen and 4 ladies. In how many ways can this be done if the committee is to be included atleast one lady? 1850 0

  • 1
    123
    Correct
    Wrong
  • 2
    113
    Correct
    Wrong
  • 3
    246
    Correct
    Wrong
  • 4
    945
    Correct
    Wrong
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Answer : 3. "246"
Explanation :

Answer: C) 246 Explanation: A Committee of 5 persons is to be formed from 6 gentlemen and 4 ladies by taking.    (i) 1 lady out of 4 and 4 gentlemen out of 6  (ii) 2 ladies out of 4 and 3 gentlemen out of 6  (iii) 3 ladies out of 4 and 2 gentlemen out of 6  (iv) 4 ladies out of 4 and 1 gentlemen out of 6    In case I the number of ways = C14×C46 = 4 x 15 = 60  In case II the number of ways = C24×C36 = 6 x 20 = 120  In case III the number of ways = C34×C26 = 4 x 15 = 60 In case IV the number of ways = C44×C16 = 1 x 6 = 6    Hence, the required number of ways = 60 + 120 + 60 + 6 = 246

Q: Out of sixty students, there are 14 who are taking Economics and 29 who are taking Calculus. What is the probability that a randomly chosen student from this group is taking only the Calculus class ? 1850 0

  • 1
    8/15
    Correct
    Wrong
  • 2
    7/15
    Correct
    Wrong
  • 3
    1/15
    Correct
    Wrong
  • 4
    4/15
    Correct
    Wrong
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Answer : 2. "7/15"
Explanation :

Answer: B) 7/15 Explanation: Given total students in the class = 60Students who are taking Economics = 24 andStudents who are taking Calculus = 32Students who are taking both subjects = 60-(24 + 32) = 60 - 56 = 4Students who are taking calculus only = 32 - 4 = 28probability that a randomly chosen student from this group is taking only the Calculus class = 28/60 = 7/15.

Q: Mirage is an example of 1849 0

  • 1
    Reflection of light & Refraction of light
    Correct
    Wrong
  • 2
    Dispersion of light
    Correct
    Wrong
  • 3
    Total Internal Reflection
    Correct
    Wrong
  • 4
    Refraction of light & Total Internal Reflection of light
    Correct
    Wrong
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Answer : 4. "Refraction of light & Total Internal Reflection of light"
Explanation :

Answer: D) Refraction of light & Total Internal Reflection of light Explanation: A Mirage is a naturally occurring optical phenomenon in which light rays bend to produce a displaced image of distant objects or the sky. It is caused due to Total internal Reflection. It is an optical illusion observed in deserts or hot summer days due to which a person sees a pond of water some distance ahead of him in which the surrounding objects appear inverted. How Mirage Forms:: 1. The temperature of other layers of atmosphere goes on decreasing as we go up.2. Therefore density and refractive index of air changes as one goes up.3. Thus a ray of light,gets refracted more and more away from the normal.4. At a particular angle when a ray of light exceeds critical angle, total internal reflection takes place and ray of light gets reflected in the same medium.5. when the reflected ray reaches our eye, it appears as coming from tree or sky .6. Hence the inverted image of tree creates an impression from a pond of water.

Q: The Value of  logtan10+logtan20+⋯⋯+logtan890 is 1848 1

  • 1
    -1
    Correct
    Wrong
  • 2
    0
    Correct
    Wrong
  • 3
    1/2
    Correct
    Wrong
  • 4
    1
    Correct
    Wrong
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Answer : 2. "0"
Explanation :

Answer: B) 0 Explanation: = log tan10+log tan890 + log tan20+ log tan880+⋯⋯+log tan450     = log [tan10 × tan890] + log [tan20 × tan880 ] +⋯⋯+log1     ∵ tan(90-θ)=cotθ and tan 450=1     = log 1 + log 1 +.....+log 1    = 0.

Q: Find the greatest number that will divide 964, 1238 and 1400 leaving remainder of 41,31 and 51 respectively ? 1848 0

  • 1
    64
    Correct
    Wrong
  • 2
    69
    Correct
    Wrong
  • 3
    71
    Correct
    Wrong
  • 4
    58
    Correct
    Wrong
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Answer : 3. "71"
Explanation :

Answer: C) 71 Explanation: To find the greatest number which divides the numbers 964, 1238 and 1400 leaving the remainders 41, 31 and 51 is nothing but the HCF of (964 - 41), (1238 - 31), (1400 - 51). Therefore, HCF of 923, 1207 and 1349 is 71.

Q: 1001 A N means 1846 0

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Answer :
Explanation :

1001 A N means 1001 Arabian Nights.   These are same as 12 S of the Z, 64 S on a C, 19 C in CB, 8 S on SS, ...

Q: According to experts what percentage of trash is recyclable? 1845 0

  • 1
    16%
    Correct
    Wrong
  • 2
    36%
    Correct
    Wrong
  • 3
    72%
    Correct
    Wrong
  • 4
    90%
    Correct
    Wrong
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Answer : 4. "90%"
Explanation :

Answer: D) 90% Explanation:

Q: A seller uses 840 gm in place of 1 kg to sell his goods. Find his actual profit/loss % When he sells his article on 4% loss on cost price ? 1842 1

  • 1
    14.28 % profit
    Correct
    Wrong
  • 2
    24.18 % profit
    Correct
    Wrong
  • 3
    14.28 % loss
    Correct
    Wrong
  • 4
    24.18 % loss
    Correct
    Wrong
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Answer : 1. "14.28 % profit"
Explanation :

Answer: A) 14.28 % profit Explanation: Let 1kg of Rs. 100 then 840gm is of Rs. 84.Now (label on can 1kg but contains 840kg ) so for customer it is of Rs. 100 and further gives 4% discount [he sells his article on 4% loss on cost price.] So now S.P = Rs. 96But actually it contains 840 gm so C.P for shopkeeper = Rs. 84S.P = Rs. 96C.P = Rs. 84Profit% = {(S.P-C.P)/C.P}x100{(96-84)/84} x 100 = 14.28571429% PROFIT.

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