IIT JEE Practice Question and Answer
8Q: A farmer divides his herd of k cows among his 4 sons, so that one son gets one half of the herd, the second gets one-fourth, the third gets one-fifth and the fourth gets 9 cows. Then k is equal to ? 1136 05b5cc73de4d2b4197774f92a
5b5cc73de4d2b4197774f92a- 1160false
- 2120false
- 3140false
- 4180true
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Answer : 4. "180"
Explanation :
Answer: D) 180 Explanation: Given total number of cows = kNow, 1st son share = k/22nd son share = k/43rd son share = k/54th son share = 9 (k) + (k/4) + (k/5) + 9 = k=> k - (19k/20) = 9=> (20k-19k)/20 = 9=> k = 180.
Q: The ratio of present ages of X and Y is 4:5. Which of the following can't be the ratio of ages of X and Y, 20 years ago ? 1451 05b5cc73de4d2b4197774f925
5b5cc73de4d2b4197774f925- 12 : 5false
- 28 : 15false
- 39 : 10true
- 43 : 5false
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Answer : 3. "9 : 10"
Explanation :
Answer: C) 9 : 10 Explanation: The ratio of X and Y ages at present is 4:5.┬а Then, the ratio 20 years ago will not be more than the ratio at present. So, from the options 9:10 is not satifying => its ratio is 0.9 which is greater than presnt ratio of 0.8.
Q: There are 3 sections with 5 questions each. If four questions are selected from each section, the chance of getting different questions is ? 828 05b5cc73de4d2b4197774f920
5b5cc73de4d2b4197774f920- 11000false
- 2625false
- 3525false
- 4125true
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Answer : 4. "125"
Explanation :
Answer: D) 125 Explanation: Methods for selecting 4 questions out of 5 in the first section = 5 x 4 x 3 x 2 x 1/4 x 3 x 2 x 1 = 5. Similarly for other 2 sections also i.e 5 and 5 So total methods = 5 x 5 x 5 = 125.
Q: Vinod have 20 rupees. He bought 1, 2, 5 rupee stamps. They are different in numbers by the reason of no change, the shop keeper gives 3 one rupee stamps. So how many stamps Vinod have ? 3816 05b5cc73de4d2b4197774f91b
5b5cc73de4d2b4197774f91b- 110true
- 218false
- 312false
- 415false
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Answer : 1. "10"
Explanation :
Answer: A) 10 Explanation: Given total rupees = 20 RsNo. of one rupee stamps = 3Now, remaining money = Rs. 17With that he buys only 2 and 5 rupee stampsLet number of Rs. 5 stamps = KLet number of Rs. 2 stamps = L5K + 2L = 17K = 3, L = 1 (possible)L = 6, K = 1 (possible)=> But given that they are different in number so, K is not equal to 3one rupee stamps = 32 two stamps = 65 rupee stamps = 1Total number of stamps = 10.
Q: There are 15 lines in plane. How many intersections (Maximum) can be made ? 1442 05b5cc73de4d2b4197774f916
5b5cc73de4d2b4197774f916- 155false
- 2105true
- 3215false
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Answer : 2. "105"
Explanation :
Answer: B) 105 Explanation: First line will cut all other 14, similarly second will cut 13, and so onTotal = 14+13+12+11+10+9+8+7+6+5+4+3+2+1 = 105.
Q: An Engine length 1000 m moving at 10 m/s. A bird is flying from engine to end with 'x' m/s and coming back at '2x' m/s. Take total time of bird travelling as 187.5 s. Find x and 2x in km/hr ? 1492 05b5cc73de4d2b4197774f911
5b5cc73de4d2b4197774f911- 121.4 and 42.8false
- 225.2 and 50.4false
- 331.4208 and 62.8416true
- 433.12 and 66.24false
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Answer : 3. "31.4208 and 62.8416"
Explanation :
Answer: C) 31.4208 and 62.8416 Explanation: Birds speeds in mtrs/sec is 'x' and '2x' .While flying from Engine to end, relative speed = (x+10) m/secfrom end to engine, flying speed = (2x - 10) mtr/secso 1000/(x+10) + 1000/(2x-10) = 187.5 secssolving it, we getso x = 8.728 m/sec and 2x= 17.456 m/sec x =┬а31.4208 km/hr and 2x =┬а62.8416 km/hr.
Q: Hemavathi gets 3 marks for each right sum and loses 2 marks for each wrong sum. He attempts 35 sums and obtains 60 marks. The number of sums attempted correctly is ? 1111 05b5cc73de4d2b4197774f90c
5b5cc73de4d2b4197774f90c- 123false
- 224false
- 325false
- 426true
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Answer : 4. "26"
Explanation :
Answer: D) 26 Explanation: Let, Hema attempted 'k' sum correctly, then k x 3 -2 x(35-k) = 605k = 130k = 26 so 26 correct sums.
Q: The sum of one-half, one-third and one-fourth of a number exceeds the number by 22. The number is 1145 05b5cc73ae4d2b4197774f907
5b5cc73ae4d2b4197774f907- 1264true
- 2284false
- 3215false
- 4302false
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Answer : 1. "264"
Explanation :
Answer: A) 264 Explanation: Let the number be 'x'. Then, from given data x/2 + x/3 + x/4 = x+2213x/12 = x+22x = 264