GATE Practice Question and Answer

Q: How many four digit even numbers can be formed using the digits {2, 7, 5, 3, 9, 1} ? 2407 0

  • 1
    59
    Correct
    Wrong
  • 2
    60
    Correct
    Wrong
  • 3
    61
    Correct
    Wrong
  • 4
    64
    Correct
    Wrong
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Answer : 2. "60"
Explanation :

Answer: B) 60 Explanation: The given digits are 1, 2, 3, 5, 7, 9   A number is even when its units digit is even. Of the given digits, two is the only even digit.Units place is filled with only '2' and the remaining three places can be filled in ⁵P₃ ways.   Number of even numbers = ⁵P₃ = 60.

Q: 12 men complete a work in 9 days. After they have worked for 6 days, 4 more men join them. How many days will they take to complete the remaining work ? 1398 0

  • 1
    2 days
    Correct
    Wrong
  • 2
    2.5 days
    Correct
    Wrong
  • 3
    2.25 days
    Correct
    Wrong
  • 4
    3 days
    Correct
    Wrong
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Answer : 3. "2.25 days"
Explanation :

Answer: C) 2.25 days Explanation: 1 man's 1 day work = 1/108 12 men's 6 day's work = 1/9 x 6 = 2/3 Remaining work = 1 - 2/3 = 1/3 16 men's 1 day work = 1/108 x 16 = 4/274/27 work is done by them in 1 day. 1/3 work is done by them in 27/4 x 1/3 = 9/4 days.

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Answer : 4. "2834"
Explanation :

Answer: D) 2834 Explanation: Let the total number of votes polled in the election be 100k.Number of valid votes = 100k - 20% (100k) = 80kLet the number of votes polled in favour of K and L be a and b respectively.a - b = 15% (100k) => a = b + 15k=> a + b = b + 15k + bNow, 2b + 15k = 80k and hence b = 32.5kIt is given that 100k = 872032.5k = 32.5k/100k x 8720 = 2834 The number of valid votes polled in favour of L is 2834.

Q: A sum of money at simple interest amounts to Rs. 415 in 2 years and to Rs. 514 in 4 years. The sum is ? 2483 0

  • 1
    Rs. 316
    Correct
    Wrong
  • 2
    Rs. 251
    Correct
    Wrong
  • 3
    Rs. 154
    Correct
    Wrong
  • 4
    Rs. 294
    Correct
    Wrong
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Answer : 1. "Rs. 316"
Explanation :

Answer: A) Rs. 316 Explanation: S.I. for 2 years = (514 - 415) = Rs. 99S.I. for 1 year = 99/2 Principal = (415 - 99) = Rs. 316.

Q: Two trains are moving in opposite directions at 60 km/hr and 90 km/hr. Their lengths are 1.10 km and 0.9 km respectively. The time taken by the slower train to cross the faster train in seconds is ? 1681 0

  • 1
    42 sec
    Correct
    Wrong
  • 2
    44 sec
    Correct
    Wrong
  • 3
    46 sec
    Correct
    Wrong
  • 4
    48 sec
    Correct
    Wrong
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Answer : 4. "48 sec"
Explanation :

Answer: D) 48 sec Explanation: Relative speed = 60 + 90 = 150 km/hr. = 150 x 5/18 = 125/3 m/sec. Distance covered = 1.10 + 0.9 = 2 km = 2000 m. Required time = 2000 x 3/125 = 48 sec.

Q: Let K and L be events on the same sample space, with P (K) = 0.8 and P (B) = 0.6. Are these two events are disjoint ? 1668 0

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    B) = 0.6. Are these two events are disjoint ? A)
    Correct
    Wrong
  • 2
    = 0.6. Are these two events are disjoint ? A) TRUE B) FALSE Answer & Explanation Answer: B) FALSE Explanation: These two events cannot be disjoint because P(K) + P(L) > 1. P(AꓴB) = P(
    Correct
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Answer : 2. "= 0.6. Are these two events are disjoint ? A) TRUE B) FALSE Answer & Explanation Answer: B) FALSE Explanation: These two events cannot be disjoint because P(K) + P(L) > 1. P(AꓴB) = P("
Explanation :

Answer: B) FALSE Explanation: These two events cannot be disjoint because P(K) + P(L) > 1. P(AꓴB) = P(A) + P(B) - P(AꓵB). An event is disjoint if P(A ꓵ B) = 0. If K and L are disjoint P(K ꓴ L) = 0.8 + 0.6 = 1.4 And Since probability cannot be greater than 1, these two mentioned events cannot be disjoint.

Q: A fair six-sided die is rolled twice. What is the probability of getting 4 on the first roll and not getting 6 on the second roll ? 1935 0

  • 1
    1/36
    Correct
    Wrong
  • 2
    5/36
    Correct
    Wrong
  • 3
    1/12
    Correct
    Wrong
  • 4
    1/9
    Correct
    Wrong
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Answer : 2. "5/36"
Explanation :

Answer: B) 5/36 Explanation: The two events mentioned are independent. The first roll of the die is independent of the second roll. Therefore the probabilities can be directly multiplied. P(getting first 4) = 1/6 P(no second 6) = 5/6 Therefore P(getting first 4 and no second 6) = 1/6 x 5/6 = 5/36

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Answer : 3. "Neither A nor B follows"
Explanation :

Answer: C) Neither A nor B follows Explanation: There is no indication that Indian scientists are incapable of developing enzymes. There could be any number of reasons why Indian scientists used Russian enzymes. So conclusion A does not follow. In addition, cost is not discussed in the passage at all. There is no mention of a correlation between cost and extraction of proteins. Thus, conclusion B does not follow either.

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