IIT JEE Practice Question and Answer

Q: How many six digit odd numbers can be formed from the digits 0, 2, 3, 5, 6, 7, 8, and 9 (repetition not allowed)? 1617 0

  • 1
    8640
    Correct
    Wrong
  • 2
    720
    Correct
    Wrong
  • 3
    3620
    Correct
    Wrong
  • 4
    4512
    Correct
    Wrong
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Answer : 1. "8640"
Explanation :

Answer: A) 8640 Explanation: Let the 6 digits of the required 6 digit number be abcdef Then, the number to be odd number the last digit must be odd digit i.e 3, 5, 7 or 9 The first digit cannot be ‘0’ => possible digits = 3, 5, 7, 2, 6, 8 Remaining 4 places can be of 6 x 5 x 4 x 3 ways This can be easily understood by Therefore, required number of ways = 6 x 6 x 5 x 4 x 3 x 4 = 36 x 20 x 12 = 720 x 12 = 8640 ways.

Q: Which of the following is the strongest acid? 1352 0

  • 1
    ClCH2COOH
    Correct
    Wrong
  • 2
    BrCH2COOH
    Correct
    Wrong
  • 3
    FCH2COOH
    Correct
    Wrong
  • 4
    ICH2COOH
    Correct
    Wrong
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Answer : 3. "FCH2COOH"
Explanation :

Answer: C) FCH2COOH Explanation: FCH2COOH is the strongest acid out of all .Since the electron withdrawing inductive effect (-I effect) of the halogens decreases in the order   F>Cl> Br> I , therefore the acidic strength of the α- halo acids decreases in the same order.   FCH2COOH  >  ClCH2COOH   >   BrCH2COOH   >   ICH2COOH.

Q: The sum of three consecutive odd numbers is 93. What is the middle number? 2152 0

  • 1
    31
    Correct
    Wrong
  • 2
    33
    Correct
    Wrong
  • 3
    29
    Correct
    Wrong
  • 4
    27
    Correct
    Wrong
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Answer : 1. "31"
Explanation :

Answer: A) 31 Explanation: Let the three consecutive odd numbers be x, x+2, x+4 Then, x + x + 2 + x + 4 = 93 => 3x + 6 = 93 => 3x = 87 => x = 29 => 29, 31, 33 are three consecutive odd numbers.   Therefore, the middle number is 31.

Q: In a college, number of boys is 75% of number of girls. Difference between boys and girls is 35. On a particular day 20% boys were absent, then find the number of boys those who present? 1534 0

  • 1
    72
    Correct
    Wrong
  • 2
    84
    Correct
    Wrong
  • 3
    93
    Correct
    Wrong
  • 4
    81
    Correct
    Wrong
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Answer : 2. "84"
Explanation :

Answer: B) 84 Explanation: Ratio of girls and boys = 100% : 75% = 4:3 Difference is 1 unit = 35 So, 3 units = 35 x 3 = 105 If 20% absent, that’s mean 80% present. So, present boys = 80% of 105 = 80×105100 = 84

Q: A train travelling with a speed of 60 km/hr catches another train travelling in the same direction and then leaves it 120m behind in 18 seconds. The speed of the second train is 1634 0

  • 1
    42 kmph
    Correct
    Wrong
  • 2
    72 kmph
    Correct
    Wrong
  • 3
    36 kmph
    Correct
    Wrong
  • 4
    44 kmph
    Correct
    Wrong
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Answer : 3. "36 kmph"
Explanation :

Answer: C) 36 kmph Explanation: Given speed of the first train = 60 km/hr = 60 x 5/18 = 50/3 m/s Let the speed of the second train = x m/s Then, the difference in the speed is given by 503 - x = 12018 => x = 10 m/s => 10 x 18/5 = 36 km/hr

Q: Hari Ram’s present age is three times his son’s present age and two fifth of his father’s present age. The average of the present age of all of them is 46 years. What is the difference between Hari Ram’s son’s present age and Hari Ram’s father’s present age? 5478 0

  • 1
    44 yrs
    Correct
    Wrong
  • 2
    56 yrs
    Correct
    Wrong
  • 3
    67 yrs
    Correct
    Wrong
  • 4
    78 yrs
    Correct
    Wrong
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Answer : 4. "78 yrs"
Explanation :

Answer: D) 78 yrs Explanation: Let Hari Ram's present age = x Then, his son's age = x/3 Father's age = 5x/2 x + x3 + 52x3 = 46=> x = 36 yrs Now the required difference = 52x36 - 363 = 78 yrs

Q: Largest Mint in India is at 1714 0

  • 1
    Mumbai
    Correct
    Wrong
  • 2
    Hyderabad
    Correct
    Wrong
  • 3
    Noida
    Correct
    Wrong
  • 4
    Kolkata
    Correct
    Wrong
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Answer : 4. "Kolkata"
Explanation :

Answer: D) Kolkata Explanation: The Largest Mint in India is Kolkata Mint.   Government of India operates 4 Mints in the country for the production of Coins. They are at Hyderabad, Telangana Mumbai, Maharashtra Kolkata, West Bengal Noida, Uttar Pradesh.

Q: 111 13 112 24 113 35 117 ? 2111 0

  • 1
    46
    Correct
    Wrong
  • 2
    57
    Correct
    Wrong
  • 3
    68
    Correct
    Wrong
  • 4
    79
    Correct
    Wrong
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Answer : 4. "79"
Explanation :

Answer: D) 79 Explanation: The given puzzle follows a pattern that, Number - . 111 - 13 112 - 24 113 - 35 So  117 - 79

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