IIT JEE Practice Question and Answer

Q: A person starting with 64 rupees and making 6 bets, wins three times and loses three times, the wins and loses occurring in random order. The chance for a win is equal to the chance for a loss. If each wager is for half the money remaining at the time of the bet, then the final result is: 4018 0

  • 1
    A gain of Rs. 27
    Correct
    Wrong
  • 2
    A loss of Rs. 37
    Correct
    Wrong
  • 3
    A loss of Rs. 27
    Correct
    Wrong
  • 4
    A gain of Rs. 37
    Correct
    Wrong
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Answer : 2. "A loss of Rs. 37"
Explanation :

Answer: B) A loss of Rs. 37 Explanation: As the win leads to multiplying the amount by 1.5 and loss leads to multiplying the amount by 0.5, we will multiply the initial amount by 1.5 thrice and by 0.5 thrice (in any order). The overall resultant will remain same. So final amount with the person will be (in all cases): = 64(1.5)(1.5)(1.5)(0.5)(0.5)(0.5)= Rs. 27 Hence the final result is:  64 − 27 = 37 A loss of Rs.37

Q: In an objective competitive exam, a correct answer score 4 marks and on a wrong answer 2 marks are negatively added. A student scores 420 marks from 150 question. How many answers were correct ? 4016 0

  • 1
    145
    Correct
    Wrong
  • 2
    138
    Correct
    Wrong
  • 3
    125
    Correct
    Wrong
  • 4
    120
    Correct
    Wrong
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Answer : 4. "120"
Explanation :

Answer: D) 120 Explanation: let x be the correct answer and y be the wrong answerso the total number of questions is (x + y) = 150.....(1)=> 4x - 2y = 420.....(2)By solving (1) & (2), we get => 6x = 720hence x = 120Therefore, number of correct answers are 120.

Q: Smallest gulf in the world is 4008 0

  • 1
    Gulf of Mexico
    Correct
    Wrong
  • 2
    Persian Gulf
    Correct
    Wrong
  • 3
    Gulf of Oman
    Correct
    Wrong
  • 4
    Gulf of California
    Correct
    Wrong
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Answer : 4. "Gulf of California"
Explanation :

Answer: D) Gulf of California Explanation: A gulf in geography is a large bay that is an arm of an ocean or sea.   The second smallest sea on Earth is the Sea of Cortez, more commonly called the Gulf of California. This sea is about 62,000 square miles. It lies between Mexico and the Baja California Peninsula.

Q: Two trains of equal length, running with the speeds of 60 and 40 kmph, take 50 seconds to cross each other while they are running in the same direction. What time will they take to cross each other if they are running in opposite directions  ? 4005 0

  • 1
    10 sec
    Correct
    Wrong
  • 2
    11 sec
    Correct
    Wrong
  • 3
    12 sec
    Correct
    Wrong
  • 4
    8 sec
    Correct
    Wrong
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Answer : 1. "10 sec"
Explanation :

Answer: A) 10 sec Explanation: Relative Speed = 60 -40 = 20 x 5/18 = 100/18 Time = 50 Distance = 50 x 100/18 = 2500/9 Relative Speed = 60 + 40 = 100 x 5/18 Time = 2500/9 x 18/500 = 10 sec.

Q: P is faster than Q. P and Q each walk 24 km. The sum of their speeds is 7 km/hr and the sum of times taken by them is 14 hours. Then, P's speed is equal to ? 4004 0

  • 1
    3 km/hr
    Correct
    Wrong
  • 2
    4 km/hr
    Correct
    Wrong
  • 3
    5 km/hr
    Correct
    Wrong
  • 4
    6 km/hr
    Correct
    Wrong
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Answer : 2. "4 km/hr"
Explanation :

Answer: B) 4 km/hr Explanation: Let P's speed = x km/hr. Then, Q's speed = (7 - x) km/ hr.   So, 24/x + 24/(7 - x) = 14   x2 - 98x + 168 = 0   (x - 3)(x - 4) = 0 => x = 3 or 4.   Since, P is faster than Q,   so P's speed = 4 km/hr and Q's speed = 3 km/hr.

Q: A company requires 12,100 strength. Present employees are 400 ladies and 6400 gents. To reach the target how many ladies required to maintain the same ratio ? 3993 0

  • 1
    400
    Correct
    Wrong
  • 2
    600
    Correct
    Wrong
  • 3
    900
    Correct
    Wrong
  • 4
    700
    Correct
    Wrong
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Answer : 3. "900"
Explanation :

Answer: C) 900 Explanation: 6,400 gents, 2400 ladies in that company.So total 8,800employees.for 8,800 employees, we want 2400 ladies.for 12,100employees we want how many ladies ?=> (12,100/8,800) x 2400 = 3300.So we want 3300 - 2400 = 900 more ladies.

Q: Which of the following contributed to the failure of prohibition? 3987 0

  • 1
    it was not imposed strictly on immigrants
    Correct
    Wrong
  • 2
    many americans didnt consider drinking to be a crime
    Correct
    Wrong
  • 3
    it adversely affected american productivity
    Correct
    Wrong
  • 4
    organized crime controlled illegal alcohol production
    Correct
    Wrong
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Answer : 4. "organized crime controlled illegal alcohol production"
Explanation :

Answer: D) organized crime controlled illegal alcohol production Explanation: Crime connected with illegal alcohol production and sale became a major issue so that even many people who had originally supported Prohibition decided that it needed to be repealed.

Q: There are three rooms in a Hotel: one single, one double and one for four persons. How many ways are there to house seven persons in these rooms ? 3983 0

  • 1
    105
    Correct
    Wrong
  • 2
    7! x 6!
    Correct
    Wrong
  • 3
    7!/5!
    Correct
    Wrong
  • 4
    420
    Correct
    Wrong
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Answer : 1. "105"
Explanation :

Answer: A) 105 Explanation: Choose 1 person for the single room & from the remaining choose 2 for the double room & from the remaining choose 4 people for the four person room,   Then, 7C1 x 6C2 x 4C4  = 7 x 15 x 1 = 105

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