IIT JEE प्रश्न और उत्तर का अभ्यास करें

प्र: Two bus tickets from city K to L and three tickets from city K to M cost Rs. 77,  but three tickets from city K to L and two tickets from city K to M cost Rs. 73. What are the fares for cities L and M from K ? 1811 0

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    Rs. 13 and Rs. 17
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  • 2
    Rs. 17 and Rs. 19
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  • 3
    Rs. 23 and Rs. 17
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  • 4
    Rs. 13 and Rs. 19
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उत्तर : 1. "Rs. 13 and Rs. 17"
व्याख्या :

Answer: A) Rs. 13 and Rs. 17 Explanation: If fares for cities L and M from K are x and y respectively, then 2x + 3y = 77 or 6x + 9y = 231...(1)3x + 2y = 73 or 6x + 4y = 146...(2) subtracting 2 from 1, we get 5y = 85 y = Rs. 17 => x = Rs. 13

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उत्तर : 4. "4"
व्याख्या :

Answer: D) 4 Explanation: Suman is brilliant and dishonest is   P ∧~ RSuman is brilliant and dishonest iff suman is rich isQ ↔  (P ∧ ~ R)   Negative of statement is expressed as~ (Q ↔(P ∧ ~ R)).

प्र: Consider 5 independent Bernoulli’s trials each with probability of success p. If the probability of at least one failure is greater than or equal to 31/32 , then p lies in the interval ? 1064 0

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    [1, 32]
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  • 2
    (0, 1)
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  • 3
    [1, 1/2]
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  • 4
    (1, 1/2]
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उत्तर : 3. "[1, 1/2]"
व्याख्या :

Answer: C) [1, 1/2] Explanation: Probability of atleast one failure= 1 - no failure > 31/32= 1 - P5 > 31/32=  P5<1/32= p < 1/2Also p > 0Hence p lies in [0,1/2].

प्र: A man saves Rs. 200 in each of the first three months of his service. In each of the subsequent months his saving increases by Rs. 40 more than the saving of immediately previous month. His total saving from the start of service will be Rs. 11040 after ? 1799 0

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    19 months
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    21 months
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    18 months
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  • 4
    20 months
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उत्तर : 2. "21 months"
व्याख्या :

Answer: B) 21 months Explanation: Total savings = 200 + 200 + 200 + 240 + 280 + ... to n months = 11040 = 120 + 80 + 160 + 40 + 200 + 240 + ....n terms= 40 + 80 + 120 + 160 + 200 + 240 + ...n terms= n/2[2a + (n-1)d] + 80 + 40 = 11040= n/2[240 + (n-1)40] = 10920= n[6+n-1] = 546= n[n+5] = 546n = 21

प्र: Three friends had dinner at a restaurant. When the bill was received, Akshitha paid 2/3 as much as Veena paid and Veena paid 1/2 as much as Lasya paid. What fraction of the bill did Veena pay ? 1424 0

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    11/3
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  • 2
    2/13
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  • 3
    3/11
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  • 4
    13/4
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उत्तर : 3. "3/11"
व्याख्या :

Answer: C) 3/11 Explanation: Let Veena paid x,so Akshitha paid 2x/3 , and Lasya paid 2x,So total bill paid is given byx+(2x/3) +2x = 1, we geti.e. x = 3/11

प्र: A bird lover was asked how many birds he had in the basket. He replied that there were all parrots but six, all pigeons but six, and all koel but six. How many birds he had in the basket in all ? 2815 0

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    8
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    18
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    9
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    10
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उत्तर : 3. "9"
व्याख्या :

Answer: C) 9 Explanation: There were all parrots but six means that six birds were not parrots but only pigeons and koels. Similarly, number of parrots + number of koels = 6 and number of parrots + number of pigeons = 6. This is possible when there are 3 parrots, 3 pigeons and 3 koels i.e. 9 birds in all.

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उत्तर : 1. "11 days"
व्याख्या :

Answer: A) 11 days Explanation: Let 'n' number of days it take to complete.   we know that sum of n number= n/2[2a+(n-1)d]where a=20,d=1;n/2[2x20+(n-1)1]=275n[n+39]=550n2 + 39n - 550 = 0 n2+ 50n - 11n - 550 = 0(n-11) (n-50) = 0n-11 = 0;n = 11(Days).

प्र: Ravi and Ramu are partners in a business.Ravi contributes 1/6 of the capital for 16 months and Ramu received 2/3 of the profit. For how long Ramu's money was used ? 1828 0

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    11 months
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  • 2
    10 months
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  • 3
    9 months
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  • 4
    8 months
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उत्तर : 4. "8 months"
व्याख्या :

Answer: D) 8 months Explanation: Let the total Profit be Z.Ramu's profit share is 2/3 of profit (i.e 2Z/3)Ravi's profit is (Z-2Z/3) =Z/3Hence the profit ratio is , Ravi : Ramu = Z/3 : 2Z/3 = 1:2 Let total Capital be Rs.X and Ramu has contributed for Y months.Since Ramu's profit share is 2/3, his invest share will be 2/3 in capital. Ravi's invest for 16 months / Ramu's invest for Y months = Ravi's profit share / Ramu's profit sharei.e. (X/6 x 16) / (2X/3 x Y) = 1/2 Solving the above equation, we get Y = 8.So Ramu's money has been used for 8 months.

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