IIT JEE Practice Question and Answer
8Q: If a 36 cm thread is used to wrap a book, lengthwise twice and breadth wise once, what is the size of the book ? 1115 05b5cc711e4d2b4197774f3dc
5b5cc711e4d2b4197774f3dc- 1288 sq.cmtrue
- 2188 sq.cmfalse
- 3144 sq.cmfalse
- 4244 sq.cmfalse
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Answer : 1. "288 sq.cm"
Explanation :
Answer: A) 288 sq.cm Explanation: Length of the thread is 36 cms. length wise twice breath wise once then totally thrice.so 36/3 = 12.so length is 12 x 2 = 24 cmsbreath is 12 cmsArea of the book = length x breath = 24 x 12 = 288 sq.cm
Q: A son and father goes for boating in river upstream . After rowing for 1 mile son notices the hat of his father falling in the river. After 5 min he tells his father that his hat has fallen. So they turn round and are able to pick the hat at the point from where they began boating after 5min. Find the speed of river in miles/hours ? 4339 05b5cc711e4d2b4197774f3d7
5b5cc711e4d2b4197774f3d7- 14 mile/hrfalse
- 26 mile/hrtrue
- 32 mile/hrfalse
- 45 mile/hrfalse
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Answer : 2. "6 mile/hr"
Explanation :
Answer: B) 6 mile/hr Explanation: Let the speed of river and boat be 'r' m/min and 'b' m/min.so relative speed in upstream (b-r)m/min and in downstream (b+r)m/min.Now in upstream distnce covered in 5 min is 5(b-r)milesso total distnce covered => 1 + 5(b-r)miles in upstreamIn downstream distance covered in 5min is 5(b+r)miles Now 1 + 5(b-r) = 5(b+r)1+5b-5r = 5b+5r1 = 10rr = 1/10 mile/min => 6 mile/hr.
Q: An amount doubles itself in 15 years. what is the rate of interest ? 1339 05b5cc711e4d2b4197774f3cd
5b5cc711e4d2b4197774f3cd- 17.85 %false
- 29.41%false
- 36.66 %true
- 44.21 %false
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Answer : 3. "6.66 %"
Explanation :
Answer: C) 6.66 % Explanation: Let the principle be Rs. PAs the amount double itself the interest is Rs. P tooSo P = P x r x 15/100=> r = 100/15 = 20/3 % = 6.66 %.
Q: A can write 32 pages in 6 hours and B can write 40 pages in 5 hours. If they write together, in how many hours they can write 110 pages ? 3689 05b5cc711e4d2b4197774f3c8
5b5cc711e4d2b4197774f3c8- 17 hrsfalse
- 26 hrs 10 minfalse
- 35 hrs 25minfalse
- 48 hrs 15 mintrue
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Answer : 4. "8 hrs 15 min"
Explanation :
Answer: D) 8 hrs 15 min Explanation: A can write in 1hour = 32/6 pages Similarly, B in 1 hour = 40/5 pages Together (A+B) in 1 hour = 32/6 + 40/5 = 40/3 So, A+B write 40/3 pages in 1 hour A+B write 110 pages in (3/40) x 110 Hours = 8 hours 15 min.
Q: If in an A.P series 18th term is 29 and 29th term is 18. Then find the 49th term ? 931 05b5cc711e4d2b4197774f3c3
5b5cc711e4d2b4197774f3c3- 1-3false
- 2-2true
- 30false
- 41false
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Answer : 2. "-2"
Explanation :
Answer: B) -2 Explanation: We know that in A.P series18th term = a + 17d29th term = a + 28dBut given a + 17d = 29..........(i)a + 28d = 18......... (ii)Solving equation (i) and (ii), we getd = -1put d = -1 in any of the above equations and we get, a = 46Now, we know 49th term can be written as, a + 48d putting the value of a and d in the above equation,a + 48d = 46 + 48(-1) = 46 - 48 = -2 Hence, the 49th term is -2.
Q: Sushma joins a job at 20 yrs. First 3 years salary is 10,000 p.a. Afterwards every year increment of 2,000 per year for 10 years. Then salary becomes constant till retirement. At retirement average salary is 25,000. (throughout career). At what age Sushma retires ? 2245 05b5cc711e4d2b4197774f3be
5b5cc711e4d2b4197774f3be- 150 yrstrue
- 247 yrsfalse
- 345 yrsfalse
- 442 yrsfalse
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Answer : 1. "50 yrs"
Explanation :
Answer: A) 50 yrs Explanation: Let age of retirement = Sso according to the given condition 25000(x-20)=10000 x 3 + 12000 + 14000 + 16000 + 18000 + 20000 + 22000 + 24000 + 26000 + 28000 + 30000 + 30000(S-33)= 30000 + 210000 + 30000S-990000= 30000S - 750000or 25000S - 500000 = 30000x - 750000or 5000x = 250000or S = 50 yrs.
Q: Rs. 50000 is divided into two parts One part is given to a person with 10% interest and another part is given to a person with 20 % interest. At the end of first year he gets profit 7000 Find money given by 10% ? 1067 05b5cc711e4d2b4197774f3b9
5b5cc711e4d2b4197774f3b9- 1Rs. 20,000false
- 2Rs. 10,000false
- 3Rs. 30,000true
- 4Rs. 40,000false
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Answer : 3. "Rs. 30,000"
Explanation :
Answer: C) Rs. 30,000 Explanation: Let first part is 'K' and second part is 'L' then K + L = 50000---------eq1Total profit = profit on x + profit on y7000 = (K x 10 x 1)/100 + (L x 20 x 1)/10070000 = K + 2L-----------------------------------eq270000 = 50000 + Lso L = 20000 then K = 50000 - 20000 = 30000first part on 10% is = Rs.30000
Q: The enzyme that converts glucose to ethyl alcohol is 1308 05b5cc711e4d2b4197774f3b4
5b5cc711e4d2b4197774f3b4- 1Maltasefalse
- 2Zymasetrue
- 3Diastasefalse
- 4Invertasefalse
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Answer : 2. "Zymase"
Explanation :
Answer: B) Zymase Explanation: