IIT JEE Practice Question and Answer

Q: Find the sum of the Arithmetic Series upto 36 terms 2, 5, 8, 11,... 1847 1

  • 1
    3924
    Correct
    Wrong
  • 2
    1962
    Correct
    Wrong
  • 3
    1684
    Correct
    Wrong
  • 4
    1452
    Correct
    Wrong
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Answer : 2. "1962"
Explanation :

Answer: B) 1962 Explanation: Arithmetic Series ::   An Arithmetic Series is a series of numbers in which each term increases by a constant amount.   How to find the sum of the Arithmetic Sequence or Series for the given Series ::   When the series contains a large amount of numbers, its impractical to add manually. You can quickly find the sum of any arithmetic sequence by multiplying the average of the first and last term by the number of terms in the sequence.   That is given by Sn = n(a1 + an)2 Where n = number of terms, a1 = first term, an = last term   Here Last term is given by an = a1 + n-1d where d = common difference   Now given Arithmetic Series is    2, 5, 8, 11,...   Here a1 = 2,  d = 3, n = 36    Now, an= a1 + n - 1d a36= 2 + 36 - 13 = 105 + 2 = 107    Now, Sum to 36 terms is given by   S36 = 36(2 + 107)2 = 36 x 1092 = 39242 = 1962       Therefore, Sum to 36 terms of the series 2, 5, 8, 11,... is 1962.

Q: Ajay and his wife Reshmi appear in an interview for two vaccancies in the same post. The Probability of Ajay's selection is 1/7 and that of his wife Reshmi's selection is 1/5. What is the probability that only one of them will be selected? 1846 0

  • 1
    5/7
    Correct
    Wrong
  • 2
    1/5
    Correct
    Wrong
  • 3
    2/7
    Correct
    Wrong
  • 4
    2/35
    Correct
    Wrong
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Answer : 3. "2/7"
Explanation :

Answer: C) 2/7 Explanation: P( only one of them will be selected) = p[(E and not F) or (F and not E)]   = PE∩F∪F∩E    = PEPF+PFPE    =17×45+15×67=27

Q: Why is DNA called the blueprint of life? 1846 0

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Answer :
Explanation :

DNA is called the blueprint of life because it contains the instructions needed for an organism to grow, develop, survive and reproduce. DNA does this by controlling protein synthesis. Proteins do most of the work in cells, and are the basic unit of structure and function in the cells of organisms.

Q: Avanthi’s age is 1/6th of her father’s age. Her father’s age will be twice of Kapil’s age after 10 years. If Kapil’s eighth birthday was celebrated two years ago, then what is Avanthi’s present age ? 1846 0

  • 1
    6 years
    Correct
    Wrong
  • 2
    4 years
    Correct
    Wrong
  • 3
    7 years
    Correct
    Wrong
  • 4
    None
    Correct
    Wrong
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Answer : 4. "None"
Explanation :

Answer: D) None Explanation: As given Kapil's 8th birthday was celebrated 2 years ago, Kapil’s present age = 8 + 2 = 10 years. Father's age is twice of Kapil’s age after 10 years. => F + 10 = 2 (K + 10) = 2 (10+ 10)F = 30years, Avanthi's age =1/6(F) = 30/6 = 5 years.

Q: DRDO full form is 1846 0

  • 1
    Delhi Research and Development Organisation
    Correct
    Wrong
  • 2
    Defence Research and Deployment
    Correct
    Wrong
  • 3
    Delhi Rail Development Organisation
    Correct
    Wrong
  • 4
    Defence Research and Development Organisation
    Correct
    Wrong
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Answer : 4. "Defence Research and Development Organisation"
Explanation :

Answer: D) Defence Research and Development Organisation Explanation: DRDO stands for The Defence Research and Development Organisation.   The Defence Research and Development Organisation (DRDO) is an agency of the Republic of India, charged with the military's research and development, headquartered in New Delhi, India.

Q: 640 ml of a mixture contains milk and water in ratio 6:2. How much of the water is to be added to get a new mixture containing half milk and half water ? 1846 0

  • 1
    360 ml
    Correct
    Wrong
  • 2
    320 ml
    Correct
    Wrong
  • 3
    310 ml
    Correct
    Wrong
  • 4
    330 ml
    Correct
    Wrong
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Answer : 2. "320 ml"
Explanation :

Answer: B) 320 ml Explanation: Here total parts of milk and water in the solution is 6+2 = 8 parts. 1part = 640/8 = 80   old mixture contains 6parts of milk and 2 parts of water(6:2).   To get new mixture containing half milk and half water, add 4parts of water to the old mixture then 6:(2+4) to make the ratio same. i.e, 4 x 80 = 320 ml.

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Answer : 4. "80"
Explanation :

Answer: D) 80 Explanation: If 'k' is number of students in P and 'l' is number of students in Q, then From the given conditions, we have=> k - 10 = l + 10 .......(1)=> k + 20 = 2(l - 20) ....(2) Solving these eqns, we get k = 100 and l = 80.Therefore, number of students in class Q is 80.

Q: Is DRAM Volatile or Nonvolatile? 1845 0

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Answer :
Explanation :

DRAM is a Volatile random-access memory (VRAM).   Volatile random-access memory (VRAM) is random-access memory that retains its information when power is turned on. Examples of volatile memory are primary storage (typically dynamic RAM, DRAM), and fast CPU cache memory (typically static RAM, SRAM, which is fast but energy-consuming and offer lower memory capacity per area unit than DRAM). Non-volatile random-access memory (NVRAM) is random-access memory that retains its information when power is turned off. Examples of non-volatile memory are flash memory (used as secondary memory) and ROM, PROM, EPROM and EEPROM memory (used for storing firmware such as BIOS).

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