GATE Practice Question and Answer
8Q: A group of men can complete a job in K hours. After every 4 hours, half the number of men working at that point of time leave the job. Continuing this way if the job is finished in 16 hours, what is the value of K ? 3359 05b5cc73ae4d2b4197774f8d8
5b5cc73ae4d2b4197774f8d8- 17 hrsfalse
- 27.5 hrstrue
- 38 hrsfalse
- 48.25 hrsfalse
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Answer : 2. "7.5 hrs"
Explanation :
Answer: B) 7.5 hrs Explanation: Let there are L men job requires LK man hours. job completed in first 4 hrs = L x 4 = 4L job completed in next 4 hrs = 4 x L/2 = 2L job completed in next 4 hrs = 4 x L/4 = L job completed in last 4 hrs = 4 x L/8 = L/2 4L + 2L + L + L/2 = KL K = 7+1/2 = 7.5 hours.
Q: 5 years ago Sushma was 5 times as old as her Son. 5 years hence her age will be 8 less than three times the corresponding age of her Son. Find their ages ? 2958 05b5cc73ae4d2b4197774f8d3
5b5cc73ae4d2b4197774f8d3- 124 and 13 yearsfalse
- 248 and 24 yearsfalse
- 335 and 11 yearstrue
- 433 and 15 yearsfalse
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Answer : 3. "35 and 11 years"
Explanation :
Answer: C) 35 and 11 years Explanation: Let the age of sushma be x and the age of her son is yThen five years before x-5=5(y-5) ...(1)Five years hence x+5 = 3(y+5)-8 .....(2) By soving (1) & (2), we get5y - 15 = 3y + 7y = 11 => x = 35 Therefore, the age of Sushma = 35 and her son = 11.
Q: Two boys are playing on a ground. Both the boys are less than 10 years old. Age of the younger boy is equal to the cube root of the product of the age of the two boys. If we place the digit representing the age of the younger boy to the left of the digit representing the age of the elder boy, we get the age of the father of the younger boy. Similarly, we place the digit representing the age of the elder boy to the left of the digit representing the age of the younger boy and divide the figure by 2, we get the age of the mother of the younger boy. The mother of the younger boy is younger than his father by 3 years. Then, what are the ages of elder and younger boys ? 3509 05b5cc73ae4d2b4197774f8ce
5b5cc73ae4d2b4197774f8ce- 1E = 15 & Y = 3false
- 2E = 14 & Y = 12false
- 3E = 40 & Y = 22false
- 4E = 4 & Y = 2true
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Answer : 4. "E = 4 & Y = 2"
Explanation :
Answer: D) E = 4 & Y = 2 Explanation: Let the the age of the elder boy = E Let the the age of the younger boy = Y Given that Y = cube root of EY => Y3 = EY => E = Y2 .....(1)By the condition of number replacement the age of the father is YE The Mother's age = EY/2 But she is 3 years less than father => EY/2 + 3 = YE2YE = EY + 6 ......(2) Then now from the given options we can identify which satisfies the all the conditions. Here Y =2 and E = 4 satisfies all the conditions.
Q: Equal quantities of three mixtures of milk and water are mixed in the ratio 1:2, 2:3 and 3:4. The ratio of water and milk in the mixture is ? 2852 05b5cc73ae4d2b4197774f8c9
5b5cc73ae4d2b4197774f8c9- 1193 : 122true
- 297 : 102false
- 3115 : 201false
- 4147 : 185false
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Answer : 1. "193 : 122"
Explanation :
Answer: A) 193 : 122 Explanation: Given the three mixtures ratio as (1:2),(2:3),(3:4) (1+2),(2+3),(3+4) Total content = 3,5,7 Given equal quantities of the three mixtures are mixed, then LCM of 3, 5, 7 = 105 105/3 = 35 , 105/5 = 21 , 105/7 = 15 Now, the individual equal quantity ratios are (35x1, 35x2), (21x2, 21x3), (15x3, 15x4) i.e (35,70), (42,63), (45,60) So overall mixture ratio of milk and water is 35+42+45 : 70+63+60 122:193 But in the question asked the ratio of water to milk = 193 : 122
Q: A man has only 20-paise and 25-paise coins in a bag. If he has 50 coins in all totaling to Rs.10.25, then the number of 20-paise coins is 898 05b5cc73ae4d2b4197774f8c4
5b5cc73ae4d2b4197774f8c4- 142false
- 245true
- 338false
- 436false
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Answer : 2. "45"
Explanation :
Answer: B) 45 Explanation: Let number of 20 ps coins = x and number of 25 ps coins = y Given total coins in the bag = 50 x + y = 50.......(1) But the total money in the bag = Rs. 10.25 0.20x + 0.25y = 10.25 20x + 25y = 1025.........(2) Now multiplying (1) by 25 we get 25x+25y=1250.............(3) By solving (2) and (3) 20x + 25y = 1025; => x = 45; Then, the no. of 20 ps coins are 45.
Q: The sum of 3rd and 15th elements of an arithmetic progression is equal to the sum of 6th, 11th and 13th elements of the same progression. Then which element of the series should necessarily be equal to zero ? 1820 15b5cc73ae4d2b4197774f8bf
5b5cc73ae4d2b4197774f8bf- 114th elementfalse
- 29th elementfalse
- 312th elementtrue
- 47th elementfalse
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Answer : 3. "12th element"
Explanation :
Answer: C) 12th element Explanation: If we consider the third term to be ‘x”The 15th term will be (x + 12d)6th term will be (x + 3d)11th term will be (x + 8d) and 13th term will be (x + 10d).Thus, as per the given condition, 2x + 12d = 3x + 21d.Or x + 9d = 0.x + 9d will be the 12th term. Thus, 12th term of the A.P will be zero.
Q: 20 men went to a restaurant. Ninteen of them paid Rs.70 each and the twentieth man paid Rs.90.25 more than the average of all the 20 men. What is the total bill ? 1480 05b5cc73ae4d2b4197774f8b5
5b5cc73ae4d2b4197774f8b5- 1Rs. 1495true
- 2Rs. 548false
- 3Rs. 850false
- 4Rs. 1750false
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Answer : 1. "Rs. 1495"
Explanation :
Answer: A) Rs. 1495 Explanation: Let the average bill paid by twenty members = 'x' But 19 men paid each = Rs. 70 20th man paid Rs. 90.25 more than the avg bill of 20 = x + 90.25 20x = 19(70) + x + 90.2519x = 1330 + 90.2519x = 1420.25x = 1420.25/19 = Rs. 74.75 But the total bill = 20 x 74.75 = Rs. 1495.
Q: If 4th december 1999 is Monday then what day is 3rd january 2000 ? 2343 05b5cc73ae4d2b4197774f8ba
5b5cc73ae4d2b4197774f8ba- 1Sundayfalse
- 2Mondayfalse
- 3Tuesdayfalse
- 4Wednesdaytrue
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Answer : 4. "Wednesday"
Explanation :
Answer: D) Wednesday Explanation: Here from 4th December 1999 to 3rd January 2000,there is a difference of 30 days.Number of odd days = 30/7 = 2 odd days Then no. of odd days = 2 => tuesday and wednesday(from monday). Hence on 3rd january it is wednesday.