IIT JEE Practice Question and Answer

Q: The ratio of present ages of Hema and Chinnu is 13:17. Four years ago the ratio of their ages was 11:15. What will be the ratio of their ages six years hence ? 2008 0

  • 1
    3 : 7
    Correct
    Wrong
  • 2
    7 : 9
    Correct
    Wrong
  • 3
    4 : 5
    Correct
    Wrong
  • 4
    1 : 3
    Correct
    Wrong
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Answer : 3. "4 : 5"
Explanation :

Answer: C) 4 : 5 Explanation: Let their present ages be 13x and 17x.Then, 13x-4/17x-4 = 11/15. Solving this, we get x = 2.Required ratio = 13x2 + 6/17x2 + 6 = 32/40 = 4/5.

Q: In following number series only one number is wrong. Find out that wrong or odd number in the series? 6, 78, 858, 7722, 54055, 270270 2008 0

  • 1
    270270
    Correct
    Wrong
  • 2
    54055
    Correct
    Wrong
  • 3
    7722
    Correct
    Wrong
  • 4
    858
    Correct
    Wrong
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Answer : 2. "54055"
Explanation :

Answer: B) 54055 Explanation: Here the given series follows a pattern that, multiplying the number with odd numbers in decreasing order starting with 13. That is,   6 × 13 = 78   65 × 11 = 858   858 × 9 = 7722   7722 × 7 = 54054   54054 × 5 = 270270   Hence, the wrong number is 54055

Q: A polygenic trait is controlled by 3 genes A, B and C. In a cross AaBbCc x AaBbCc, the phenotypic ratio of the offsprings was observed as 1 : 6 : m : 20 : m : 6 : 1. What is the value of m? 2008 0

  • 1
    10
    Correct
    Wrong
  • 2
    15
    Correct
    Wrong
  • 3
    18
    Correct
    Wrong
  • 4
    24
    Correct
    Wrong
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Answer : 2. "15"
Explanation :

Answer: B) 15 Explanation: Here crossing is AaBbCc x AaBbCc As it is trihybrid cross, we know, Number of zygotes formed = 4n, where n = 3 43 = 64 Given ratio of offsprings = 1 : 6 : m : 20 : m : 6 : 1 Now,  1 + 6 + m + 20 + m + 6 + 1 = 64 34 + 2m = 64 2m = 30 => m = 15.

Q: Which statement is one component of the cell theory? 2007 0

  • 1
    DNA is the basis of genetic transfer
    Correct
    Wrong
  • 2
    All living cells arise from pre-existing cells
    Correct
    Wrong
  • 3
    All cells are composed of same organelles
    Correct
    Wrong
  • 4
    Tissues are formed from combinations of cells
    Correct
    Wrong
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Answer : 2. "All living cells arise from pre-existing cells"
Explanation :

Answer: B) All living cells arise from pre-existing cells Explanation: All living cells arise from pre-existing cells is one component of the cell theory.   The Cell Theory is one of the basic principles of biology.   The Cell Theory states: 1. All living organisms are composed of cells. They may be unicellular or multicellular. 2. The cell is the basic unit of life. 3. Cells arise from pre-existing cells.

Q: A class has 8 football players. A 5-member team and a captain will be selected out of these 8 players. How many different selections can be made ? 2007 0

  • 1
    210
    Correct
    Wrong
  • 2
    168
    Correct
    Wrong
  • 3
    1260
    Correct
    Wrong
  • 4
    10!/6!
    Correct
    Wrong
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Answer : 2. "168"
Explanation :

Answer: B) 168 Explanation: we can select the 5 member team out of the 8 in 8C5 ways = 56 ways. The captain can be selected from amongst the remaining 3 players in 3 ways. Therefore, total ways the selection of 5 players and a captain can be made = 56x3 = 168 ways.   (or)   Alternatively, A team of 6 members has to be selected from the 8 players. This can be done in 8C6 or 28 ways. Now, the captain can be selected from these 6 players in 6 ways. Therefore, total ways the selection can be made is 28x6 = 168 ways.

Q: The Hardest substance available on Earth is 2007 0

  • 1
    Diamond
    Correct
    Wrong
  • 2
    Wurtzite
    Correct
    Wrong
  • 3
    Platinum
    Correct
    Wrong
  • 4
    Gold
    Correct
    Wrong
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Answer : 1. "Diamond"
Explanation :

Answer: A) Diamond Explanation: Diamond is the hardest substance available on Earth. Diamond is the hardest substance available on Earth due to the giant molecular structure of diamond in which each carbon atom is covalently bonded to four other carbon atoms. A covalent bond is very strong and requires a large amount of energy to break itself, and diamond has many covalent bonds.

Q: Please enter the Missing number: 4 8 14 22 ? 2006 0

  • 1
    28
    Correct
    Wrong
  • 2
    32
    Correct
    Wrong
  • 3
    46
    Correct
    Wrong
  • 4
    36
    Correct
    Wrong
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Answer : 2. "32"
Explanation :

Answer: B) 32 Explanation: Here the given series follows a pattern that, 22 - 0 = 4   32 - 1 = 8   42 - 2 = 14 52 - 3 = 22 62 - 4 = 32 Hence, the missing number is 32     Method 2 :: The difference between 4 and 8 is 4, the difference between 8 and 14 is 6, the difference between 14 and 22 is 8. So the next difference between 22 and the next number will be 10 since it follows (4,6,8,10 - add +2 each time) Hence, 22 + 10 = 32 is the missing number.

Q: Vishal and Raghu jointly started a business. Vishal invested three times as Raghu did and invested his money for double time as compared to Raghu. Raghu earned Rs. 4000. If the gain is proportional to the money invested and the time for which the money is invested then the total gain was  ? 2006 0

  • 1
    Rs. 28,000
    Correct
    Wrong
  • 2
    Rs. 18,000
    Correct
    Wrong
  • 3
    Rs. 14,000
    Correct
    Wrong
  • 4
    Rs. 8,000
    Correct
    Wrong
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Answer : 1. "Rs. 28,000"
Explanation :

Answer: A) Rs. 28,000 Explanation: Investments ratio is = 3:1Time period ratio is = 2:1 As they are proportional to gain ------Gain ratio of Vishal and raghu = 6:1 But given Raghu got Rs. 4000,  =? 1 ----- 4000     7 -----    ? => Rs.28,000 The total gain = Rs.28,000

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