IIT JEE Practice Question and Answer

Q: Virus doubles every 3 mins. It is 'K' in 1 hour, when was it K/4 ? 1497 0

  • 1
    29 min
    Correct
    Wrong
  • 2
    25 min
    Correct
    Wrong
  • 3
    54 min
    Correct
    Wrong
  • 4
    57 min
    Correct
    Wrong
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Answer : 3. "54 min"
Explanation :

Answer: C) 54 min Explanation: If virus is K in 1hr i.e 60 minthen in 57 min it was K/2 as it doubles every 3 minutes=> In 54 min it was K/4.At 54 minutes it was K/4.

Q: In a class, seven students are standing in a row. Q is standing left to R but right to P. O is standing right to N and left to P. Similarly, S is standing right to R and left to T. Find out who is standing in the middle ? 1723 0

  • 1
    Q
    Correct
    Wrong
  • 2
    R
    Correct
    Wrong
  • 3
    P
    Correct
    Wrong
  • 4
    S
    Correct
    Wrong
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Answer : 1. "Q"
Explanation :

Answer: A) Q Explanation: As from the given conditions;Order is N O P Q R S THere the student standing in the middle is 'Q'.

Q: What is better, to have 70% discount or 40 and 30% discount consequently ? 2380 0

  • 1
    40% is better
    Correct
    Wrong
  • 2
    70% is better
    Correct
    Wrong
  • 3
    Both are same
    Correct
    Wrong
  • 4
    None
    Correct
    Wrong
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Answer : 2. "70% is better"
Explanation :

Answer: B) 70% is better Explanation: Let Price be Rs.100 1st CASE: Then 100 x 70/100 = 70=> price after discount = 100-70 = Rs.30 2nd CASE: Then 100 x 40/100 = 40=> price after discount = 100-40 = Rs.60then60 x 30/100 = 18=> price after 2 consequent discount = 60-18 = Rs.42 =>from 1 and 2 cases, 70% discount is better.

Q: In a row, Kumar is at 7th place from the left and Pawan is at 9th place from the right. When they interchange the positions Kumar becomes 11th from left. How many were seated in the row ? 3197 0

  • 1
    19
    Correct
    Wrong
  • 2
    20
    Correct
    Wrong
  • 3
    21
    Correct
    Wrong
  • 4
    27
    Correct
    Wrong
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Answer : 1. "19"
Explanation :

Answer: A) 19 Explanation: Initialy from left 7th = kumarfrom right 9th = pawanInterchange kumar = 11th from left, from right kumar = 9th;11+8 = 19;8 is 1,2,3,4,5,6,7(pawan),8,9,10,11(kumar),12,13,14,15,16,17,18,19;simply count the 9th place from right we will get total as 19.

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Answer : 4. "11 & 9"
Explanation :

Answer: D) 11 & 9 Explanation: Let the number of apples in each tree of the 5 farmers be a, b, c, d,e respectively. Therefore total no of apples are 7a, 9b, 11c, 13d and 14e respectively. Given, 7a+1 = 9b+3 = 11c-1 = 13d+3 = 14e-6 = x 9b+3 = 13d+3===> 9b = 13dso take b = 13 and d = 9 9b+3 = 9*13+3 = 120 ie, x=120 substituting7a+1 = 1207a = 119a = 17 11c-1 = 12011c = 121c=11 14e-6 = 12014e = 126e = 9 Yields per tree in the orchards of d 3rd & 4th farmers= 11,9

Q: Which alphabet replaces the question mark ? 63 O 4972 T 3796 L 1514 ? 58 3591 0

  • 1
    A
    Correct
    Wrong
  • 2
    B
    Correct
    Wrong
  • 3
    C
    Correct
    Wrong
  • 4
    D
    Correct
    Wrong
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Answer : 3. "C"
Explanation :

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

Q: If Reena’s age was twice of her present age, when subtracted from four times three years from hence, with three times the three years before her present age. What will be her age after one year ? 1593 0

  • 1
    22 yrs
    Correct
    Wrong
  • 2
    21 yrs
    Correct
    Wrong
  • 3
    20 yrs
    Correct
    Wrong
  • 4
    24 yrs
    Correct
    Wrong
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Answer : 1. "22 yrs"
Explanation :

Answer: A) 22 yrs Explanation: Let Reena’s present age be 'K' yrs.Given:{(K+3) x 4} - {(K-3) x 3)} => K = 21 yrsSo her present age is 21 yrs.Then, her age after 1 year is 22 yrs.

Q: Four persons can cross a bridge in 3,7,13,17 minutes.Only two can cross at a time.Find the minimum time taken by the four to cross the bridge ? 4571 0

  • 1
    17 minutes
    Correct
    Wrong
  • 2
    20 minutes
    Correct
    Wrong
  • 3
    34 minutes
    Correct
    Wrong
  • 4
    12 minutes
    Correct
    Wrong
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Answer : 2. "20 minutes"
Explanation :

Answer: B) 20 minutes Explanation: First send 17 and 7. After 7 minutes, 7 is at finish and 17 needs 10 more minutes to complete his travel. now send 13. After 10 minutes 17 reaches finish and 13 needs 3 more minutes to complete. now send 3. both 3 and 13 reach destination at the same time after 3 minutes. hence the time taken is 7+10+3=20 minutes.

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