IIT JEE Practice Question and Answer

Q: Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 4 or 15 ? 995 0

  • 1
    6/19
    Correct
    Wrong
  • 2
    3/10
    Correct
    Wrong
  • 3
    7/10
    Correct
    Wrong
  • 4
    6/17
    Correct
    Wrong
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Answer : 2. "3/10"
Explanation :

Answer: B) 3/10 Explanation: Here, S = {1, 2, 3, 4, ...., 19, 20}=> n(s) = 20Let E = event of getting a multiple of 4 or 15 =multiples od 4 are {4, 8, 12, 16, 20}And multiples of 15 means multiples of 3 and 5= {3, 6 , 9, 12, 15, 18, 5, 10, 15, 20}.= the common multiple is only (15).=> E = n(E)= 6Required Probability = P(E) = n(E)/n(S) = 6/20 = 3/10.

Q: Which company is now listed to be one of the world's most valuable privately held companies ? 994 0

  • 1
    Space X
    Correct
    Wrong
  • 2
    Tata Steels
    Correct
    Wrong
  • 3
    Facebook
    Correct
    Wrong
  • 4
    Apple
    Correct
    Wrong
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Answer : 1. "Space X"
Explanation :

Answer: A) Space X Explanation:

Q: A tap can fill a tank in 6 hours. After half the tank is filled three more similar taps are opened. What is the total time taken to fill the tank completely ? 994 0

  • 1
    4 hrs 15 min
    Correct
    Wrong
  • 2
    3 hrs 24 min
    Correct
    Wrong
  • 3
    4 hrs 51 min
    Correct
    Wrong
  • 4
    3 hrs 45 min
    Correct
    Wrong
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Answer : 4. "3 hrs 45 min"
Explanation :

Answer: D) 3 hrs 45 min Explanation: Time taken by one tap to fill half of the tank = 3 hrs. Part filled by the taps in 1 hour = 4 x 1/6 = 2/3 Remaining part = 1 - 1/2 = 1/2 2/3 : 1/2 :: 1 : p p = 1/2 x 1 x 3/2 = 3/4 hrs. i.e., 45 min So, total time taken = 3 hrs 45 min.

Q: Two trains running in opposite directions cross a pole placed on the platform in 47 seconds and 31 seconds respectively. If they cross each other in 33 seconds, what is the ratio of their speeds? 994 0

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

Answer: A) 1:7 Explanation: Let the speed of the trains be x and y respectively length of train1 = 47xlength of train2 = 31yRelative speed= x + yTime taken to cross each other = 33 s=> 47x+31yx+y= 33=> (47x + 31 y) = 33(x + y)=> 14x = 2y=> x/y = 2/14 = 1/7  = 1:7

Q: Multiplicative inverse of 7? 993 0

  • 1
    1
    Correct
    Wrong
  • 2
    -1/7
    Correct
    Wrong
  • 3
    0
    Correct
    Wrong
  • 4
    1/7
    Correct
    Wrong
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Answer : 4. "1/7"
Explanation :

Answer: D) 1/7 Explanation: Multiplicative inverse is nothing but a reciprocal of a number.  It is defined as one of a pair of numbers that when multiplied with another number equals the number 1. Multiplicative inverse or reciprocal of 7 is  7 x n = 1 => n = 1/7.   Hence, Multiplicative inverse or reciprocal of 7 is  1/7.

Q: The Human Resource Development Ministry and the External Affairs Ministry launched an online verification portal ___________ to make the document verification process easier. 993 0

  • 1
    e-bharat
    Correct
    Wrong
  • 2
    e-sanad
    Correct
    Wrong
  • 3
    e-foriegn
    Correct
    Wrong
  • 4
    e-verify
    Correct
    Wrong
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Answer : 2. "e-sanad"
Explanation :

Answer: B) e-sanad Explanation: The Human Resource Development Ministry and the External Affairs Ministry launched an online verification portal to make the document verification process easier for students who planning to study abroad. The Central Board of Secondary Education’s (CBSE) academic repository of degrees and certificates “Parinam Manjusha” was also involved in the project of creating “eSanad”.

Q: Who has won the Nobel prize in "Physics" for the year 2017 ? 993 0

  • 1
    Barry Barish
    Correct
    Wrong
  • 2
    Kip Thorne
    Correct
    Wrong
  • 3
    Rainer Weiss
    Correct
    Wrong
  • 4
    All of the above
    Correct
    Wrong
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Answer : 4. "All of the above"
Explanation :

Answer: D) All of the above Explanation: Rainer Weiss, a professor at the Massachusetts Institute of Technology, and Kip Thorne and Barry Barish, both of the California Institute of Technology, were awarded the Nobel Prize in Physics for the discovery of ripples in space-time known as gravitational waves, which were predicted by Albert Einstein a century ago but had never been directly seen.

Q: Everyone has it and no one can lose it. What is it? 991 0

  • 1
    Face
    Correct
    Wrong
  • 2
    Teeth
    Correct
    Wrong
  • 3
    Hair
    Correct
    Wrong
  • 4
    Shadow
    Correct
    Wrong
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Answer : 4. "Shadow"
Explanation :

Answer: D) Shadow Explanation:

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