IIT JEE Practice Question and Answer

Q: Sound waves cannot travel in 3677 0

  • 1
    Vacuum
    Correct
    Wrong
  • 2
    Water
    Correct
    Wrong
  • 3
    Glass
    Correct
    Wrong
  • 4
    Hydrogen gas
    Correct
    Wrong
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Answer : 1. "Vacuum"
Explanation :

Answer: A) Vacuum Explanation: A Sound wave needs a medium for propogation. Hence, Sound cannot travel through a vacuum. A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibrations to work in.

Q: The oldest type of energy known to man is _____? 3676 0

  • 1
    Geothermal Energy
    Correct
    Wrong
  • 2
    Solar Power
    Correct
    Wrong
  • 3
    Wind Power
    Correct
    Wrong
  • 4
    Tidal Power
    Correct
    Wrong
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Answer : 1. "Geothermal Energy"
Explanation :

Answer: A) Geothermal Energy Explanation: Geothermal energy is heat energy generated and stored in the Earth. Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.

Q: A Certain sum of money an amounts to Rs 2500 in a span Of 5 years and further to Rs.3000 in a span of 7 years at simple interest The sum is ? 3674 0

  • 1
    Rs. 1800
    Correct
    Wrong
  • 2
    Rs. 2000
    Correct
    Wrong
  • 3
    Rs. 1400
    Correct
    Wrong
  • 4
    Rs. 1250
    Correct
    Wrong
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Answer : 4. "Rs. 1250"
Explanation :

Answer: D) Rs. 1250 Explanation: 2500 in 5th year and 3000 in 7th year So in between 2 years Rs. 500 is increased => for a year 500/2 = 250So, per year it is increasing Rs.250 then in 5 years => 250 x 5 = 1250Hence, the initial amount must be 2500 - 1250 = Rs. 1250

Q: Find the least number by which 175760 be divided to make it a perfect cube. 3674 0

  • 1
    6
    Correct
    Wrong
  • 2
    10
    Correct
    Wrong
  • 3
    9
    Correct
    Wrong
  • 4
    30
    Correct
    Wrong
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Answer : 2. "10"
Explanation :

Answer: B) 10 Explanation: 175760 =2³ x 2 x 5 x 13³= 2³ x 2 x 5 x 13³ To make perfect cube, it must be divided by 2 x 5 = 10

Q: Find the number of factors of 9321 ? 3654 0

  • 1
    4
    Correct
    Wrong
  • 2
    5
    Correct
    Wrong
  • 3
    7
    Correct
    Wrong
  • 4
    8
    Correct
    Wrong
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Answer : 4. "8"
Explanation :

Answer: D) 8 Explanation: 9321 = 3 x 13 x 239 = 31 x 13 1 x 239 1 ; add one to all the powers ie., (1+1) x (1+1) x (1+1)= 8 ; we get eight factors.

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Answer : 4. "149600 kgs"
Explanation :

Answer: D) 149600 kgs Explanation: Let the total quantity of gold be p kgs. According to the question, 50% of p + 25% of p + 12.5% of p = 130900 87.5% of p = 130900 p = 130900 x 100/87.5  = 149600 kgs.   Therefore, the initial gold quantity that king has = p = 149600 kgs.

Q: In a class 60% of the students pass in English and 45% pass in Hindi. If 25% of them pass in both subjects, what percentage of the students fail in both the subjects? 3647 1

  • 1
    20%
    Correct
    Wrong
  • 2
    25%
    Correct
    Wrong
  • 3
    30%
    Correct
    Wrong
  • 4
    15%
    Correct
    Wrong
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Answer : 1. "20%"
Explanation :

Answer: A) 20% Explanation: Percentage of students passed in English = 60% Percentage of students passed in Hindi = 45% Percentage of students passed in both subjects = 25% ATQ, Percentage of students passed in only English = 60 - 25 = 35% Percentage of students passed in only Hindi = 45 - 25 = 20% Therefore, Percentage of students failed = 100 - (35 + 25 + 20) = 100 - 80 = 20%.

Q: A milkman claims to sell milk at its cost price, still, he is making a profit of 30% since he has mixed some amount of water in the milk. What is the % of milk in the mixture? 3646 0

  • 1
    71.02%
    Correct
    Wrong
  • 2
    76.92%
    Correct
    Wrong
  • 3
    63.22%
    Correct
    Wrong
  • 4
    86.42%
    Correct
    Wrong
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Answer : 2. "76.92%"
Explanation :

Answer: B) 76.92% Explanation: Let the milk he bought is 1000 ml Let C.P of 1000 ml is Rs. 100 Here let he is mixing K ml of water He is getting 30% profit => Now, the selling price is also Rs. 100 for 1000 ml => 100 : K% = 100 : 30 10 : 3 is ratio of milk to water => Percentage of milk = 10 x 100/13 = 1000/13 = 76.92%

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