GATE Practice Question and Answer

Q: There are 15 lines in plane. How many intersections (Maximum) can be made ? 1443 0

  • 1
    55
    Correct
    Wrong
  • 2
    105
    Correct
    Wrong
  • 3
    215
    Correct
    Wrong
  • 4
    148
    Correct
    Wrong
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Answer : 2. "105"
Explanation :

Answer: B) 105 Explanation: First line will cut all other 14, similarly second will cut 13, and so onTotal = 14+13+12+11+10+9+8+7+6+5+4+3+2+1 = 105.

Q: Hemavathi gets 3 marks for each right sum and loses 2 marks for each wrong sum. He attempts 35 sums and obtains 60 marks. The number of sums attempted correctly is ? 1111 0

  • 1
    23
    Correct
    Wrong
  • 2
    24
    Correct
    Wrong
  • 3
    25
    Correct
    Wrong
  • 4
    26
    Correct
    Wrong
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Answer : 4. "26"
Explanation :

Answer: D) 26 Explanation: Let, Hema attempted 'k' sum correctly, then k x 3 -2 x(35-k) = 605k = 130k = 26 so 26 correct sums.

Q: The sum of one-half, one-third and one-fourth of a number exceeds the number by 22. The number is 1145 0

  • 1
    264
    Correct
    Wrong
  • 2
    284
    Correct
    Wrong
  • 3
    215
    Correct
    Wrong
  • 4
    302
    Correct
    Wrong
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Answer : 1. "264"
Explanation :

Answer: A) 264 Explanation: Let the number be 'x'. Then, from given data x/2 + x/3 + x/4 = x+2213x/12 = x+22x = 264

Q: A single pipe of diameter x has to be replaced by six pipes of diameters 12 cm each. The pipes are used to covey some liquid in a laboratory. If the speed/flow of the liquid is maintained the same then the value of x is ? 1507 0

  • 1
    14.69 cm
    Correct
    Wrong
  • 2
    29.39 cm
    Correct
    Wrong
  • 3
    18.65 cm
    Correct
    Wrong
  • 4
    22.21 cm
    Correct
    Wrong
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Answer : 2. "29.39 cm"
Explanation :

Answer: B) 29.39 cm Explanation: Volume of water flowing through 1 pipe of diameter x = Volume discharged by 6 pipes of diameter 12 cms.   As speed is same, area of cross sections should be same.    Area of bigger pipe of diameter x = Total area of 6 smaller pipes of diameter 12  i.e πR2 = 6πR12    Here R = R and R1 = 12/2 = 6    ⇒R2 = 6×6×6    R = 14.696    => D = X = 14.696 * 2 = 29.3938 cm.

Q: Population of a colony of mosquitoes is increasing by 20% per day. If the population on Monday was 3000, on which day of that week the population would be 5184 ? 1453 0

  • 1
    Thursday
    Correct
    Wrong
  • 2
    Friday
    Correct
    Wrong
  • 3
    Tuesday
    Correct
    Wrong
  • 4
    Monday
    Correct
    Wrong
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Answer : 1. "Thursday"
Explanation :

Answer: A) Thursday Explanation: Given monday population = 3000Per day 20% increase in population. Tuesday population = 3000 + 3000x20/100 = 3000 + 600 = 3600 Wednesday population =3600 + 3600x20/100 = 3600 + 720 = 4320 Thursday population = 4320 + 4320x20/100 = 4320 + 864 = 5184 So that day is Thursday.

Q: Two parallel chords on the same side of the centre of a circle are 5 cm apart. If the chords are 20 and 28 cm long, what is the radius of the circle? 973 0

  • 1
    14.69 cm
    Correct
    Wrong
  • 2
    15.69 cm
    Correct
    Wrong
  • 3
    18.65 cm
    Correct
    Wrong
  • 4
    16.42 cm
    Correct
    Wrong
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Answer : 2. "15.69 cm"
Explanation :

Answer: B) 15.69 cm Explanation: Draw the two chords as shown in the figure. Let O be the center of the circle. Draw OC perpendicular to both chords. That divides the two chords in half.So CD = 10 and AB = 14. Draw radii OA and OD, both equal to radius r.We are given that BC = 5, the distance between the two chords. LetOB = x. We use the Pythagorean theorem on right triangle ABO AO² = AB² + OB² r² = 14² + x² We use the Pythagorean theorem on right triangle DCO DO² = CD² + OC² We see that OC = OB+BC = x+5, so r² = 10² + (x+5)² So we have a system of two equations: r² = 14² + x² r² = 10² + (x+5)² Since both left sides equal r², set the right sidesequal to each other. 14² + x² = 10² + (x+5)² 196 + x² = 100 + x² + 10x + 25 196 = 125 + 10x 71 = 10x 7.1 = x r² = 14² + x² r² = 196 + (7.1)² r² = 196 + 50.41 r² = 246.41 r = √246.41 r = 15.69745202 cm

Q: An express train takes 4 seconds to enter tunnel which is 1 km long. If it is traveling at 108 km an hour, how long will it take to pass completely through the tunnel ? 1303 0

  • 1
    33 sec
    Correct
    Wrong
  • 2
    37.33 sec
    Correct
    Wrong
  • 3
    36.43 sec
    Correct
    Wrong
  • 4
    32 sec
    Correct
    Wrong
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Answer : 2. "37.33 sec"
Explanation :

Answer: B) 37.33 sec Explanation: Speed = 108 km/hrenter a tunnel,, means that the train covers a distance equal to its own lengthso (108 x 5/18) = x/4 where x= length of trainhence x = 120 mtrsto pass completely train has to travel a distance = (x + tunnel length) that is 1120 mtrs.so (1120/t) = (108x5/18)t = 37.33 sec

Q: Three strategies P, Q and R have been initiated for cost cutting in a company producing respectively 20%, 30% and 10% savings. Assuming that they operate independently, what is the net saving achieved ? 1694 0

  • 1
    49.6%
    Correct
    Wrong
  • 2
    50.4%
    Correct
    Wrong
  • 3
    33.67%
    Correct
    Wrong
  • 4
    66.66%
    Correct
    Wrong
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Answer : 1. "49.6%"
Explanation :

Answer: A) 49.6% Explanation: As these three strategies P, Q and R are independent so these will cut cost one after the other.If initial cost is Rs 100, then20% cost is cut after initializing strategy P, then cost will remain 80% = 80further 30% cost is cut after strategy Q, then cost will remain 70% of 80 = 56further 10% cost is cut after strategy R, then cost will remain 90% of 56 = 50.4 Thus final cost remains 50.4 % of the original cost. Hence net saving is 100 - 50.4 = 49.6 %.

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