IIT JEE Practice Question and Answer

Q: The value of a machine depreciates at the rate of 10% every year. It was purchased 3 years ago. If its present value is Rs. 8,748, its purchase price was ? 3659 0

  • 1
    Rs.14,000
    Correct
    Wrong
  • 2
    Rs.12,000
    Correct
    Wrong
  • 3
    Rs. 12,800
    Correct
    Wrong
  • 4
    Rs. 15,000
    Correct
    Wrong
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Answer : 2. "Rs.12,000"
Explanation :

Answer: B) Rs.12,000 Explanation: We have P = 8748, R = -10 and n = 3Therefore, the purchase price of the machine= P1+R100n= 87481-101003= 8748 x (100/90) x (100/90) x (100/90)= 12,000.   Therefore, the purchase price of the machine was Rs. 12,000.

Q: Divide Rs.118000 among three persons A, B and C such that the ratio of the shares of A and B is 3:4 and that of B:C is 5:6 ? 3659 0

  • 1
    A = 48000 B = 40000 C = 30000
    Correct
    Wrong
  • 2
    A = 30000 B = 40000 C = 48000
    Correct
    Wrong
  • 3
    A = 30000 B = 48000 C = 40000
    Correct
    Wrong
  • 4
    A = 40000 B = 48000 C = 30000
    Correct
    Wrong
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Answer : 2. "A = 30000 B = 40000 C = 48000"
Explanation :

Answer: B) A = 30000 B = 40000 C = 48000 Explanation: Compound ratio of A:B:CA:B = 3:4B:C = 5:6----------A:B:C = 15:20:24 We can divide Rs.118000 in this ratio. Share of A = 15/59 x 118000 = 30000 Share of B = 20/59 x 118000 = 40000 Share of C = 24/59 x 118000 = 48000

Q: The average weight of a group of boys is 30 kg. After a boy of weight 35 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally ? 3658 0

  • 1
    6
    Correct
    Wrong
  • 2
    8
    Correct
    Wrong
  • 3
    4
    Correct
    Wrong
  • 4
    5
    Correct
    Wrong
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Answer : 3. "4"
Explanation :

Answer: C) 4 Explanation: Let the number of boys in the group originally be x.Total weight of the boys = 30xAfter the boy weighing 35 kg joins the group, total weight of boys = 30x + 35So 30x + 35 + 31(x + 1) = > x = 4.

Q: Tennis rackets and ballpoint pens are 3658 0

  • 1
    complementary goods
    Correct
    Wrong
  • 2
    independent goods
    Correct
    Wrong
  • 3
    inferior goods
    Correct
    Wrong
  • 4
    substitute goods
    Correct
    Wrong
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Answer : 2. "independent goods"
Explanation :

Answer: B) independent goods Explanation: Tennis rackets and ballpoint pens are two independent goods. Since, one doesn't depend on the other.

Q: A does half as much work as Band C does half as much work as A and B together. If C alone can finish the work in 40 days, then together ,all will finish the work in  ? 3656 0

  • 1
    17 + 4/7 days
    Correct
    Wrong
  • 2
    13 + 1/3 days
    Correct
    Wrong
  • 3
    15 + 3/2 days
    Correct
    Wrong
  • 4
    16 days
    Correct
    Wrong
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Answer : 2. "13 + 1/3 days"
Explanation :

Answer: B) 13 + 1/3 days Explanation: C alone can finish the work in 40 days.As given C does half as much work as A and B together => (A + B) can do it in 20 days(A + B)s 1 days wok = 1/20.A's 1 days work : B's 1 days Work = 1/2 : 1 = 1:2(given)A's 1 day’s work = (1/20) x (1/3) = (1/60) [Divide 1/20 in the raio 1:2]B's 1 days work = (1/20) x (2/3) = 1/30(A+B+C)'s 1 day's work = (1/60) + (1/30) + (1/40) = 9/120 = 3/40 All the three together will finish it in 40/3 = 13 and 1/3 days.

Q: P and Q were assigned to do a work for an amount of 1200. P alone can do it in 15 days while Q can do it in 12 days. With the help of R they finish the work in 6 days. Find the share of R ? 3653 0

  • 1
    120
    Correct
    Wrong
  • 2
    240
    Correct
    Wrong
  • 3
    360
    Correct
    Wrong
  • 4
    180
    Correct
    Wrong
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Answer : 1. "120"
Explanation :

Answer: A) 120 Explanation: 1/15 + 1/12 + 1/R = 1/6, we got R = 60 (it means R will take 60 days to complete the work alone) so ratio of work done by P:Q:R = 1/15 : 1/12 : 1/60 = 5 : 4 : 1 so R share = (1/10) x 1200 = 120.

Q: 96% of the population of a village is 23040. The total population of the village is ? 3650 0

  • 1
    24000
    Correct
    Wrong
  • 2
    32256
    Correct
    Wrong
  • 3
    25478
    Correct
    Wrong
  • 4
    26587
    Correct
    Wrong
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Answer : 1. "24000"
Explanation :

Answer: A) 24000 Explanation: Let the total population be 'P' P x (96/100) = 23040 P = 240 * 100 P = 24000.

Q: How is my father's brother's only sibling's mother related to my sister's only brother ? 3648 0

  • 1
    Neice
    Correct
    Wrong
  • 2
    Aunt
    Correct
    Wrong
  • 3
    Mother
    Correct
    Wrong
  • 4
    Grand-mother
    Correct
    Wrong
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Answer : 4. "Grand-mother"
Explanation :

Answer: D) Grand-mother Explanation: My father's brother's only sibling is my father. My father's mother is my grandmother. My sister's only brother is myself. So she is my Grandmother.

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