IIT JEE Practice Question and Answer

Q: A motorboat goes 8 km an hour in still water, but takes thrice as much time in going the same distance against the current than going with the current. Then find the speed of the current? 2430 0

  • 1
    4 kmph
    Correct
    Wrong
  • 2
    6 kmph
    Correct
    Wrong
  • 3
    3 kmph
    Correct
    Wrong
  • 4
    2 kmph
    Correct
    Wrong
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Answer : 1. "4 kmph"
Explanation :

Answer: A) 4 kmph Explanation: Let the speed of current = 'C' km/hr   Given the speed of boat in still water = 6 kmph   Let 'd' kms be the distance it covers.   According to the given data,   Boat takes thrice as much time in going the same distance against the current than going with the current   i.e, d8 - C = 3 × d8 + C   ⇒ 24 - 3C = 8 + C⇒ 4C = 16⇒ C = 4 kmph   Hence, the speed of the current C = 4 kmph.

Q: A Conical tent was erected by the army at a base camp with height 3 m and base diameter 10 m. If every person requires 3.92 cu.m air, then how many persons can be seated in that tent approximately? 2430 0

  • 1
    20
    Correct
    Wrong
  • 2
    19
    Correct
    Wrong
  • 3
    17
    Correct
    Wrong
  • 4
    22
    Correct
    Wrong
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Answer : 1. "20"
Explanation :

Answer: A) 20 Explanation: Given height of the conical tent = 3 m Diameter = 10 => Radius = D/2 = 10/2 = 5 m  Now, as the tent is in the conical form Volume of the conical tent = πr2h3  => (22 x 5 x 5 x 3) / (7 x 3)  = 22 x 25/7  = 78.54 cu.m  Given each person requires 3.92 cu.m of air  => Number of persons can be seated in the tent = 78.54/3.92 = 20.03 =~ 20

Q: In how many ways word of 'GLACIOUS' can be arranged such that 'C' always comes at end? 2430 0

  • 1
    3360
    Correct
    Wrong
  • 2
    5040
    Correct
    Wrong
  • 3
    720
    Correct
    Wrong
  • 4
    1080
    Correct
    Wrong
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Answer : 2. "5040"
Explanation :

Answer: B) 5040 Explanation: Given word is GLACIOUS has 8 letters. => C is fixed in one of the 8 places Then, the remaining 7 letters can be arranged in 7! ways = 5040.

Q: A train covers a distance between station A and station B in 45 min.If the speed of the train is reduced by 5 km/hr,then the same distance is covered in 48 min.what is the distance between the stations A and B ? 2430 0

  • 1
    80 kms
    Correct
    Wrong
  • 2
    60 kms
    Correct
    Wrong
  • 3
    45 kms
    Correct
    Wrong
  • 4
    32 kms
    Correct
    Wrong
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Answer : 2. "60 kms"
Explanation :

Answer: B) 60 kms Explanation: Let 'd' be the distance and 's' be the speed and 't' be the timed=sxt45 mins = 3/4 hr and 48 mins = 4/5 hrAs distance is same in both cases;s(3/4) = (s-5)(4/5)3s/4 = (4s-20)/515s = 16s-80s = 80 km.=> d = 80 x 3/4 = 60 kms.

Q: What will be the cost of building a fence around a square plot with area equal to 289 sq ft, if the price per foot of building the fence is Rs. 58 ? 2430 0

  • 1
    Rs. 3748
    Correct
    Wrong
  • 2
    Rs. 3847
    Correct
    Wrong
  • 3
    Rs. 3944
    Correct
    Wrong
  • 4
    Rs. 3154
    Correct
    Wrong
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Answer : 3. "Rs. 3944"
Explanation :

Answer: C) Rs. 3944 Explanation: Let the side of the square plot be 'a' ft.Given area of the plot (a x a) = 289 => a = 17Length of the fence = Perimeter of the plot = 4a = 68 ft.Cost of building the fence = 68 x 58 = Rs. 3944.

Q: The average temperature for Monday, Tuesday, Wednesday and Thursday was 48 degrees and for Tuesday, Wednesday, Thursday and Friday was 46 degrees. If the temperature on Monday was 42 degrees. Find the temperature on Friday ? 2428 0

  • 1
    34
    Correct
    Wrong
  • 2
    36
    Correct
    Wrong
  • 3
    38
    Correct
    Wrong
  • 4
    40
    Correct
    Wrong
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Answer : 1. "34"
Explanation :

Answer: A) 34 Explanation: M + Tu + W + Th = 4 x 48 = 192Tu + W + Th + F = 4 x 46 = 184M = 42Tu + W + Th = 192 - 42 = 150F = 184 – 150 = 34

Q: In a class of 50 students M is eighth from top. H is 20th from bottom. How many students are there between M and H? 2426 0

  • 1
    22
    Correct
    Wrong
  • 2
    23
    Correct
    Wrong
  • 3
    24
    Correct
    Wrong
  • 4
    can't be determined
    Correct
    Wrong
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Answer : 1. "22"
Explanation :

Answer: A) 22 Explanation: M is 8th from the top.   H is (50 - 20 + 1 =) 31 st from the top.   Number of students between M and H = (31 - 8- 1=)22

Q: Which of the following is Not an Operating System? 2426 0

  • 1
    UNIX
    Correct
    Wrong
  • 2
    Windows NT
    Correct
    Wrong
  • 3
    C++
    Correct
    Wrong
  • 4
    DOS
    Correct
    Wrong
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Answer : 3. "C++"
Explanation :

Answer: C) C++ Explanation: C++ is not an Operating System.   An Operating System is a collection of system programs that manages all the other programs application programs in a computer as well as the allocation and use of hardware resources such as the CPU, Memory and the Hard Disk Drive. It acts as an interface between the hardware and the user level program. It controls and facilitates the overall operation of a computer.    Here UNIX : UNIX is a popular multi-user, multitasking operating system (OS) developed at Bell Labs.   Windows NT : Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993.   DOS : DOS is Disk Operating System. The term DOS can refer to any operating system.   C++ : C++ is a programming language and computing platform.   Hence, C++ is not an Operating System.

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