GATE Practice Question and Answer

Q: Which of the following is biodegradable? 3693 0

  • 1
    Iron nails
    Correct
    Wrong
  • 2
    DDT
    Correct
    Wrong
  • 3
    Silver foil
    Correct
    Wrong
  • 4
    Leather bags
    Correct
    Wrong
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Answer : 4. "Leather bags"
Explanation :

Answer: D) Leather bags Explanation: Biodegradable substances can be broken down into simpler, harmless substances in nature with due course of time by the biological process such as action of microbes. They can be recycled as a part of food chain.   Here, Leather bags are biodegradable.

Q: A man swims downstream 72 km and upstream 45 km taking 9 hours each time; what is the speed of the current  ? 3692 0

  • 1
    1 kmph
    Correct
    Wrong
  • 2
    3.2 kmph
    Correct
    Wrong
  • 3
    1.5 kmph
    Correct
    Wrong
  • 4
    2 kmph
    Correct
    Wrong
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Answer : 3. "1.5 kmph"
Explanation :

Answer: C) 1.5 kmph Explanation: 72 --- 9 ? ---- 1 => Down Stream = 8 45 ---- 9 ? ---- 1 => Up Stream = 5 Speed od current S = ? S = (8 - 5)/2 = 1.5 kmph.

Q: A group of men can complete a job in K hours. After every 4 hours, half the number of men working at that point of time leave the job. Continuing this way if the job is finished in 16 hours, what is the value of K ? 3686 0

  • 1
    7 hrs
    Correct
    Wrong
  • 2
    7.5 hrs
    Correct
    Wrong
  • 3
    8 hrs
    Correct
    Wrong
  • 4
    8.25 hrs
    Correct
    Wrong
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Answer : 2. "7.5 hrs"
Explanation :

Answer: B) 7.5 hrs Explanation: Let there are L men job requires LK man hours.   job completed in first 4 hrs = L x 4 = 4L job completed in next 4 hrs = 4 x L/2 = 2L job completed in next 4 hrs = 4 x L/4 = L job completed in last 4 hrs = 4 x L/8 = L/2 4L + 2L + L + L/2 = KL K = 7+1/2 = 7.5 hours.

Q: What is the main component of biogas and natural gas? 3678 0

  • 1
    Carbon dioxide
    Correct
    Wrong
  • 2
    Butane
    Correct
    Wrong
  • 3
    Hydrogen Sulphide
    Correct
    Wrong
  • 4
    Methane
    Correct
    Wrong
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Answer : 4. "Methane"
Explanation :

Answer: D) Methane Explanation: Methane is the main component of biogas and natural gas.

Q: The two trains of lengths 400 m, 600 m respectively, running at same directions. The faster train can cross the slower train in 180 sec, the speed of the slower train is 48 kmph. Then find the speed of faster train  ? 3677 0

  • 1
    68 kmph
    Correct
    Wrong
  • 2
    52 kmph
    Correct
    Wrong
  • 3
    76 kmph
    Correct
    Wrong
  • 4
    50 kmph
    Correct
    Wrong
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Answer : 1. "68 kmph"
Explanation :

Answer: A) 68 kmph Explanation: Let the speed of the faster train be 'X' kmph, Then their relative speed= X - 48 kmphTo cross slower train by faster train, Distance need to be cover = (400 + 600)m = 1 km. and Time required = 180 sec = 180/3600 hr = 1/20 hr.Time = Distance/Speed => 1/20 = 1/(x-48)X = 68 kmph

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Answer : 2. "Rs.17,500"
Explanation :

Answer: B) Rs.17,500 Explanation: Let’s assume John bought the laptop for Rs. 100He then sells it to Mark at a loss of 20% => Rs. 80,Who consequently sells it to Kevin at a profit of 25% =>  Rs. 100Then, Kevin sells it back to Mark for Rs. 90 (Rs.4.50 for every Rs. 5 that he had paid initially), so he suffers a loss of Rs. 10Therefore, for Rs. 100 there is a loss of Rs. 10,Then for Rs. 1,75,000 there will be a loss of Rs. 17,500.

Q: Two trains, one from Hyderabd to Bangalore and the other from Bangalore to Hyderabad, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is  ? 3673 0

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

Answer: B) 4 : 3 Explanation: Let us name the trains as A and B. Then, (A's speed) : (B's speed) = √b : √a = √16 : √9 = 4:3

Q: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 3661 0

  • 1
    70 years
    Correct
    Wrong
  • 2
    30 years
    Correct
    Wrong
  • 3
    60 years
    Correct
    Wrong
  • 4
    40 years
    Correct
    Wrong
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Answer : 2. "30 years"
Explanation :

Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

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