Practice Question and Answer
8Q: Which two method you need to implement for key Object in HashMap ? 1280 05b5cc6dee4d2b4197774ea7f
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Answer :
Explanation :
In order to use any object as Key in HashMap, it must implements equals and hashcode method in Java.
Q: What is immutable object? Can you write immutable object ? 1535 05b5cc6dee4d2b4197774ea7e
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Answer :
Explanation :
Immutable classes are Java classes whose objects can not be modified once created. Any modification in Immutable object result in new object. For example is String is immutable in Java. Mostly Immutable are also final in Java, in order to prevent sub class from overriding methods in Java which can compromise Immutability. You can achieve same functionality by making member as non final but private and not modifying them except in constructor.
Q: The circumferences of two circles are 264 meters and 352 meters. Find the difference between the areas of the larger and the smaller circles ? 3117 05b5cc6dee4d2b4197774ea79
5b5cc6dee4d2b4197774ea79- 12413 sq.mfalse
- 21234 sq.mfalse
- 34312 sq.mtrue
- 42143 sq.mfalse
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Answer : 3. "4312 sq.m"
Explanation :
Answer: C) 4312 sq.m Explanation: Let the radii of the smaller and the larger circles be 's' m and 'l' m respectively. 2πs = 264 and 2πl = 352 s = 2642π and l = 3522π Difference between the areas =πl2-πs2 = π1762π2-1322π2 = 1762π-1322π = (176 - 132)(176 + 132) / π = (44 x 308) / (22/7) = 4312 sq.m
Q: The compound interest earned by Sunil on a certain amount at the end of two years at the rate of 8% p.a. was Rs.2828.80. Find the total amount that Sunil got back at the end of two years in the form of principal plus interest earned ? 2176 05b5cc6dee4d2b4197774ea74
5b5cc6dee4d2b4197774ea74- 1Rs. 11828.80false
- 2Rs. 19828.80true
- 3Rs. 9828.80false
- 4Rs. 19328.80false
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Answer : 2. "Rs. 19828.80"
Explanation :
Answer: B) Rs. 19828.80 Explanation: Let the sum be Rs. P P{ 1+81002- 1 } = 2828.80 It is in the form of a2-b2 = a+ba-b P(8/100)(2 + 8/100) = 2828.80 P = 2828.80 / (0.08)(2.08) = 1360/0.08 = 17000 Principal + Interest = Rs. 19828.80
Q: Rifath Sharook has designed the world’s lightest satellite “KalamSat”. He hails from which country ? 1272 05b5cc6dee4d2b4197774ea6f
5b5cc6dee4d2b4197774ea6f- 1Russiafalse
- 2Pakistanfalse
- 3Dubaifalse
- 4Indiatrue
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Answer : 4. "India"
Explanation :
Answer: D) India Explanation: Indian teen Rifath Sharook from Tamil Nadu has designed the world’s lightest & smallest satellite named “KalamSat”. The satellite weighs only 64 grams and will be launched by NASA on June 21, 2017. With this, he will become the first Indian student to have his experiment launched by NASA. The main role of the satellite will be to demonstrate the performance of 3-D printed carbon fibre. The satellite has been designed in a way which will have a 240-minute mission in space and will operate for 12 minutes in a micro-gravity environment of space.
Q: When I went back to my hometown three years ago, I found that a lot of changes ______. 5006 05b5cc6dee4d2b4197774ea6a
5b5cc6dee4d2b4197774ea6a- 1were taken placefalse
- 2are taken placefalse
- 3had taken placetrue
- 4have taken placefalse
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Answer : 3. "had taken place"
Explanation :
Answer: C) had taken place Explanation: Since he is telling about the thing that had happened in past.
Q: There are 100 students in 3 sections A, B and C of a class. The average marks of all the three sections was 84. The average of B and C was 87.5 and the average marks of students in A section was : 4167 05b5cc6dee4d2b4197774ea65
5b5cc6dee4d2b4197774ea65- 120true
- 235false
- 354false
- 440false
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Answer : 1. "20"
Explanation :
Answer: A) 20 Explanation: Numbers of students in section A = x ∴ Numbers of students in section B and C = (100 – x) ∴ x 70 + (100 – x) 87.5 = 84 100 => 70x + 87.5 100 – 87.5x = 8400 => 8750 – 17.5x = 8400 => 17.5x = 8750 – 8400 => x = 20.
Q: The arithmetic mean of the following numbers 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6 and 7, 7, 7, 7, 7, 7, 7 is ? 2265 05b5cc6dee4d2b4197774ea60
5b5cc6dee4d2b4197774ea60- 16false
- 29false
- 37false
- 45true
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Answer : 4. "5"
Explanation :
Answer: D) 5 Explanation: Arithmatic mean = sum/members => (1x1 + 2x2 + 3x3 + 4x4 + 5x5 + 6x6 + 7x7) / (1 + 2 + 3 + 4 + 5 + 6 + 7) => 140/28 = 5