IIT JEE Practice Question and Answer
8Q: K can build a wall in 30 days. L can demolish that wall in 60 days. If K and L work on alternate days, when will the wall be completed ? 3063 15b5cc6f8e4d2b4197774f081
5b5cc6f8e4d2b4197774f081- 1120 daysfalse
- 2119 daysfalse
- 3118 daysfalse
- 4117 daystrue
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Answer : 4. "117 days"
Explanation :
Answer: D) 117 days Explanation: K's work in a day(1st day) = 1/30L's work in a day(2nd day)= -1/60(demolishing)hence in 2 days, combined work= 1/30 - 1/60 =1/60since both works alternatively, K will work in odd days and L will work in even days.1/60 unit work is done in 2 days58/60 unit work will be done in 2 x 58 days = 116 daysRemaining work = 1-58/60 = 1/30Next day, it will be K's turn and K will finish the remaining 1/30 work.hence total days = 116 + 1 = 117.
Q: A Woman’s downstream swimming rate is thrice of her upstream swimming rate. If she covers 12 km upstream in 2.5 hours, what distance she will cover in 5 hours downstream? 3060 05b5cc639e4d2b4197774ba82
5b5cc639e4d2b4197774ba82- 172 kmtrue
- 236 kmfalse
- 356 kmfalse
- 442 kmfalse
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Answer : 1. "72 km"
Explanation :
Answer: A) 72 km Explanation: Rate of her upstream = 12/2.5 = 4.8 km/hr Then, ATQ Rate of downstream = 4.8 x 3 = 14.4 km/hr Hence, the distance she covers downstream in 5 hrs = 14.4 x 5 = 72 kms.
Q: When a women sells 20 articles for Rs. 160, there is 40% loss. How many articles should she sell for Rs. 240 in order to earn 20% profit ? 3055 05b5cc6c2e4d2b4197774dbc3
5b5cc6c2e4d2b4197774dbc3- 116false
- 215true
- 317false
- 414false
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Answer : 2. "15"
Explanation :
Answer: B) 15 Explanation: Given when she sells at Rs. 160 for 20 articles, she get 40% loss. Then, to get 20% profit selling at Rs. 240 for let 'P' articles => 1602060=240p120 => 120 x 160 x P = 20 x 70 x 240 => P = 15 articles.
Q: Which of the following memories needs refresh ? 3053 65b5cc6c0e4d2b4197774db0a
5b5cc6c0e4d2b4197774db0a- 1DRAMtrue
- 2ROMfalse
- 3SRAMfalse
- 4All of the abovefalse
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Answer : 1. "DRAM"
Explanation :
Answer: A) DRAM Explanation:
Q: fifteen persons are sitting around a circular table facing the centre. What is the probability that three particular persons sit together ? 3046 05b5cc731e4d2b4197774f7dd
5b5cc731e4d2b4197774f7dd- 13/91true
- 22/73false
- 31/91false
- 43/73false
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Answer : 1. "3/91"
Explanation :
Answer: A) 3/91 Explanation: In a circle of n different persons, the total number of arrangements possible = (n - 1)!Total number of arrangements = n(S) = (15 – 1)! = 14 !Taking three persons as a unit, total persons = 13 (in 4 units)Therefore no. of ways for these 13 persons to around the circular table = (13 - 1)! = 12!In any given unit, 3 particular person can sit in 3!. Hence total number of ways that any three person can sit =n(E) = 12! X 3!Therefore P (E) = probability of three persons sitting together = n(E) / n(S) = 12! X 3 ! / 14!= 12!x3x2 / 14x13x12! = 6/14x13 = 3/91
Q: On a ruler's tombstone, it is said that one sixth of his life was spent in childhood and one twelfth as a teenager. One seventh of his life passed between the time he became an adult and the time he married; five years later, his son was born. Alas, the son died four years before he did. He lived to be twice as old as his son did. How old did the ruler live to be ? 3041 05b5cc741e4d2b4197774f981
5b5cc741e4d2b4197774f981- 184 yearstrue
- 272 yearsfalse
- 382 yearsfalse
- 464 yearsfalse
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Answer : 1. "84 years"
Explanation :
Answer: A) 84 years Explanation: Let the age of ruler is x so that of son = x/2 (given)Now according to the given condition (x/6) + (x/12) + (x/7) + 5 + (x/2) + 4 = x=> x = 84
Q: Pipe K fills a tank in 30 minutes. Pipe L can fill the same tank 5 times as fast as pipe K. If both the pipes were kept open when the tank is empty, how much time will it take for the tank to overflow ? 3039 05b5cc75ee4d2b4197774fcc5
5b5cc75ee4d2b4197774fcc5- 13 minutesfalse
- 22 minutesfalse
- 34 minutesfalse
- 45 minutestrue
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Answer : 4. "5 minutes"
Explanation :
Answer: D) 5 minutes Explanation: Let the total capacity of tank be 90 liters.Capacity of tank filled in 1 minute by K = 3 liters.Capacity of tank filled in 1 minute by L = 15 liters.Therefore, capacity of the tank filled by both K and L in 1 minute = 18 liters.Hence, time taken by both the pipes to overflow the tank = 90/18 = 5 minutes.
Q: Which statement about greek sculpture is false? 3038 05b5cc639e4d2b4197774ba6c
5b5cc639e4d2b4197774ba6c- 1The Greeks admired the strength and precision of athletes and wanted to portray athletic figures.false
- 2The three main principles of Greek aesthetics are proportion, movement, and rhythm.false
- 3Greeks sculptures are typically stiffly posed, highly styled figures.true
- 4All the abovefalse
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Answer : 3. "Greeks sculptures are typically stiffly posed, highly styled figures."
Explanation :
Answer: C) Greeks sculptures are typically stiffly posed, highly styled figures. Explanation: Greek Sculpture are typically stiff, posed & highly styled figures is the false answer.