IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: Which alphabet replaces the question mark ? 63 O 4972 T 3796 L 1514 ? 58 4144 0

  • 1
    A
    सही
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  • 2
    B
    सही
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  • 3
    C
    सही
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  • 4
    D
    सही
    गलत
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उत्तर : 3. "C"
व्याख्या :

Answer: C) C Explanation: 6-3 = 3 9-4 = 5 (3x5=15) 15=O7-2 = 5 7-3 = 4 (5x4=20) 20=T9-6 = 3 5-1 = 4 (3x4=12) 12=L Similarly, 4-1 = 3 8-5 = 1 (3x1=3) 3=C

प्र: If there are 150 questions in a 3 hr examination. Among these questions 50 are type A problems, which requires twice as much as time be spent on the rest of the type B problems. How many minutes should be spent on type A problems ? 4139 0

  • 1
    75 min
    सही
    गलत
  • 2
    82 min
    सही
    गलत
  • 3
    90 min
    सही
    गलत
  • 4
    101 min
    सही
    गलत
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उत्तर : 3. "90 min"
व्याख्या :

Answer: C) 90 min Explanation: Let X = Time taken for each of Type B Problems(100 Problems)And 2X = Time taken for each of Type A problems(50 problems) Total time period = 3hrs = 3 x 60min = 180 minutes 100X + 50(2X) = 180100X + 100X = 180200X = 180 min X = 180/200X = 0.90 min By convertiing into seconds, X = 0.90 x 60 secondsX = 54 sec So, time taken for Part A problems is = 54 x 2 x 50 = 5400 seconds= 5400/60sec = 90 minutes.

प्र: What is the main component of biogas and natural gas? 4131 0

  • 1
    Carbon dioxide
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  • 2
    Butane
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  • 3
    Hydrogen Sulphide
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  • 4
    Methane
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उत्तर : 4. "Methane"
व्याख्या :

Answer: D) Methane Explanation: Methane is the main component of biogas and natural gas.

प्र: A vertical toy 18 cm long casts a shadow 8 cm long on the ground. At the same time a pole casts a shadow 48 m. long on the ground. Then find the height of the pole ? 4122 0

  • 1
    1080 cm
    सही
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  • 2
    180 m
    सही
    गलत
  • 3
    108 m
    सही
    गलत
  • 4
    118 cm
    सही
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उत्तर : 3. "108 m"
व्याख्या :

Answer: C) 108 m Explanation: We know the rule that,   At particular time for all object , ratio of height and shadow are same.   Let the height of the pole be 'H'   Then  188=H48   => H = 108 m.

प्र: Two solutions have milk & water in the ratio 7:5 and 6:11. Find the proportion in which these two solutions should Be mixed so that the resulting solution has 1 part milk and 2 parts water ? 4118 0

  • 1
    7 : 12
    सही
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  • 2
    8 : 13
    सही
    गलत
  • 3
    9 : 4
    सही
    गलत
  • 4
    2 : 5
    सही
    गलत
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उत्तर : 2. "8 : 13"
व्याख्या :

Answer: B) 8 : 13 Explanation: To get the solution that contains 1 part of milk and two parts of water,they must be mixed in the ratio as7x+6x/5y+11y = 1/226x = 16yx/y = 16/26x/y = 8/13

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उत्तर : 2. "30 min"
व्याख्या :

Answer: B) 30 min Explanation: Distance travelled by Ramu = 45 x 4 = 180 km Somu travelled the same distance in 6 hours. His speed = 180/6 = 30 km/hr Hence in the conditional case, Ramu's speed = 45 - 9 = 36 km/hr and Somu's speed = 30 + 10 = 40km/hr. Therefore travel time of Ramu and Somu would be 5 hours and 4.5 hours respectively. Hence difference in the time taken = 0.5 hours = 30 minutes.

प्र: The day before yesterday, I was 25 years old, and next year I will turn 28. How is it possible? 4109 0

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उत्तर :
व्याख्या :

On carefully inspecting this question, one can understand that there are two days which are important and these are: A. My Birthday. B. The day when I am making this statement. If you think for a while, you will understand that such statements can be made only around the year’s end. So, if my birthday is on 31 December, then I will be making this statement on 1 January. I will further explain using the following example: 1. Consider that today is 01 January 2017. 2. Then, the day before yesterday was 30 December 2016 and according to the question I was 25 then. 3. Yesterday was 31 December 2016, which happens to be my birthday too (Woohoo!), and my age increases by one to become 26. 4. I will turn 27 on my birthday this year (31 December 2017). 5. I will turn 28 on my birthday next year (31 December 2018). Now, if you read the question again, it will make more sense:   The day before yesterday(30 December 2016), I was 25 years old and next year(31 December 2018) I will be 28.

प्र: Ten years ago, Karan was thrice as old as Shiva was but 10 years hence, he will be only twice as old. Find Shiva’s present age ? 4098 0

  • 1
    70 years
    सही
    गलत
  • 2
    30 years
    सही
    गलत
  • 3
    60 years
    सही
    गलत
  • 4
    40 years
    सही
    गलत
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उत्तर : 2. "30 years"
व्याख्या :

Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

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