IIT JEE Practice Question and Answer

Q: If 12 men can reap 120 acres of land in 36 days, how many acres of land can 54 men reap in 54 days? 3386 0

  • 1
    710 acres
    Correct
    Wrong
  • 2
    760 acres
    Correct
    Wrong
  • 3
    810 acres
    Correct
    Wrong
  • 4
    860 acres
    Correct
    Wrong
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Answer : 3. "810 acres"
Explanation :

Answer: C) 810 acres Explanation: 12 men120 acres36 days54 men?54 days  As 12 men can reap 120 acres, 54 men will be able to reap more acres in 36 days, 120 acres of land was reaped, so in 54 days, more land will be reaped.   Thus, the numbers of acres that can be reaped by 54 men in 54 days = 5412x120x5436 = 810 acres

Q: CK169JROS2419TXKM??PV 1751 0

  • 1
    14,21
    Correct
    Wrong
  • 2
    21,14
    Correct
    Wrong
  • 3
    56,84
    Correct
    Wrong
  • 4
    84,56
    Correct
    Wrong
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Answer : 2. "21,14"
Explanation :

Answer: B) 21,14 Explanation: Putting A=1, B=2, C=3,..., M=13,....,X=24,Y=25, Z=26, we have :        JR = J + R2 + 2 = 10 + 18 2 + 2 = 16       CK = C + K2 + 2 =  3 + 112 + 2 = 9       TX = T + X2+ 2 = 20 + 242 + 2 = 24       OS = O + S2 + 2 = 15 + 192 + 2 = 19        So, the missing numbers are :       21 and 14       Hence, the answer is (b).

Q: If A + B = 2C and C + D = 2A, then 5634 0

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

Answer: A) A + C = B + D Explanation: Given,   A + B = 2C ----(i)   C + D = 2A----(ii)   Adding (i) and (ii) we get : A + B + C + D = 2C + 2A   =>  B + D = A + C

Q: Sumanth walks 200 feet straight from his house, which is facing north and then he walks 100 feet in reverse direction.Further he takes a left turn and walks 300 yards.In Which direction is Sumanth now from his original position? 1712 0

  • 1
    South-East
    Correct
    Wrong
  • 2
    North-East
    Correct
    Wrong
  • 3
    South-West
    Correct
    Wrong
  • 4
    North-West
    Correct
    Wrong
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Answer : 2. "North-East"
Explanation :

Answer: B) North-East Explanation: Starting From his house, Sumanth walks 200 feet straight towards North; we can write it as N200. Similarly, the other distances and directions can be considered and written as follows : (Notice that he covers 300 yards towards East; one yard = 3 feet and hence 300 yards = 900 feet)  N200S100E900 Adding all south and all North distances and finding the net result, and also adding all East and all West distances and finding the net result, this can further be summarized as : N100E900  Thus, the direction from his original position is North-East.

Q: A boat loaded with rocks floats in the middle of a swimming pool. A man in the boat throws the rocks overboard. The level of water in the pool will 1237 0

  • 1
    increase
    Correct
    Wrong
  • 2
    decrease
    Correct
    Wrong
  • 3
    remains the same
    Correct
    Wrong
  • 4
    first decrease and then increase
    Correct
    Wrong
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Answer : 2. "decrease"
Explanation :

Answer: B) decrease Explanation: Let M and m grams be the mass of boat + rock in it. By law of floatation(M+m) grams of water will be displaced. This has a volume of (M+m)cc. That means the level of water in pool has risen up by (M+m)cc with the boat + rock when it is floating. If the rocks in the boat are thrown not into the pool but outside, the weight left is only M grams the weight of the boat. This will have displaced M cc of water only i.e less water than in the case of loaded boat. But if the rocks are put in the water in the pool and not outside, then the water in the pool will rise not only by M cc on account of empty boat but also by a volume of the stone put into it. This volume will be mdwhere m is the mass of rock and d density of rock. Now md is  < m. Thus the total rise will be M+mdwhich is < M + m.

Q: At what temperature do the Fahrenheit and celcius scales give the same reading? 1432 0

  • 1
    212 degrees
    Correct
    Wrong
  • 2
    32 degreees
    Correct
    Wrong
  • 3
    -40 degreees
    Correct
    Wrong
  • 4
    0 degreees
    Correct
    Wrong
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Answer : 3. "-40 degreees"
Explanation :

Answer: C) -40 degreees Explanation: We want the temperature when F=C. We know that, F = C x 95 + 32 So substituting C For F, we have C = -40o Therefore,  C = -40.  Thus when C = -40, we have C = F

Q: Fish and other aquatic creatures can live inside a deep frozen pond because 2326 0

  • 1
    fish are cold-blooded animals
    Correct
    Wrong
  • 2
    ice is a bad conductor of heat
    Correct
    Wrong
  • 3
    there will always be water just beneath the ice level
    Correct
    Wrong
  • 4
    they can adapt themselves to live in ice
    Correct
    Wrong
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Answer : 3. "there will always be water just beneath the ice level"
Explanation :

Answer: C) there will always be water just beneath the ice level Explanation: Water has the maximum density at 4oC. So at this temperature, it sinks down to bottom and stays here. If it cools further, it will become less dense and move up. So while the upper layers can cool enough to form ice, the bottom layers remain as water at  4oC .   Therefore, (C) is correct.

Q: In a plane 8 points are colliner  out of 12 points, then the number of triangles we get with those 12 points is 969 0

  • 1
    20
    Correct
    Wrong
  • 2
    160
    Correct
    Wrong
  • 3
    164
    Correct
    Wrong
  • 4
    220
    Correct
    Wrong
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Answer : 3. "164"
Explanation :

Answer: C) 164 Explanation: For a triangle, we need 3 non-collinear points. So with 12 points (when all the 12 are such that any three non-collinear is12C3. But among them 8 points are collinear.   If all these 8 points are different we get 8C3 triangles as they are collinear.   In 12C3 triangles, we do not get 8C3 triangles   Therefore, The number of triangles we get = 12C3-8C3 = 164

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