IIT JEE Practice Question and Answer
8Q: An individual deposited 20% of 25% of 30% of what he had into his account with a bank. If he deposited Rs.750, how much was he having initially with him before depositing ? 1433 05b5cc71ee4d2b4197774f595
5b5cc71ee4d2b4197774f595- 1Rs. 38000false
- 2Rs. 47000false
- 3Rs. 50000true
- 4Rs. 35000false
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Answer : 3. "Rs. 50000"
Explanation :
Answer: C) Rs. 50000 Explanation: Let 'x' be the amount he had in the bank. => 20/100(25/100(30/100(x))) = 750 x = 750 x 8000/120 = Rs. 50000
Q: In how many ways can the letters of the word 'LEADER' be arranged ? 1012 05b5cc71ee4d2b4197774f58b
5b5cc71ee4d2b4197774f58b- 1360true
- 2420false
- 3576false
- 4220false
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Answer : 1. "360"
Explanation :
Answer: A) 360 Explanation: No. of letters in the word = 6No. of 'E' repeated = 2Total No. of arrangement = 6!/2! = 360
Q: A boat travels 72 km downstream in 8 hours and 84 km upstream in 12 hours. Find the speed of the boat in still water and the speed of the water current ? 1533 05b5cc71ee4d2b4197774f581
5b5cc71ee4d2b4197774f581- 19 and 3 kmphfalse
- 26 and 7 kmphfalse
- 38 and 1 kmphtrue
- 47 and 2 kmphfalse
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Answer : 3. "8 and 1 kmph"
Explanation :
Answer: C) 8 and 1 kmph Explanation: Downstream speed = 72km/8hrs = 9 kmphupstream speed = 84km/12hrs = 7 kmphspeed of boat = avg of downstream and upstream speedsspeed of boat = (9+7)/2kmph = 8 kmph.current speed = half of the difference of downstream and upstream speedscurrend speed = (9-7)/2kmph = 1 kmph
Q: A train moving at 2/3 rd of its normal speed reaches its destination 20 minutes late. Find the normal time taken ? 2911 05b5cc71ee4d2b4197774f57c
5b5cc71ee4d2b4197774f57c- 14/3 hrsfalse
- 22/3 hrstrue
- 33/2 hrsfalse
- 41/4 hrsfalse
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Answer : 2. "2/3 hrs"
Explanation :
Answer: B) 2/3 hrs Explanation: Let the original speed and time is S and Tthen distance = S x TNow the speed changes to 2/3S and T is T+20As the distance is sameS x T = 2/3Sx(T+20)solving this we get t = 40 minutes =40/60 = 2/3 hour
Q: On sport’s day, if 12 children were made to stand in each column, 98 columns could be formed. After a certain music being played the plan was that the children have to stand in concentric circles such that the innermost circle will have one student, the next circle will have two students, the third circle will have 3 students and so on. How many circles will be formed in this manner ? 1742 05b5cc71ee4d2b4197774f577
5b5cc71ee4d2b4197774f577- 144false
- 246false
- 348true
- 449false
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Answer : 3. "48"
Explanation :
Answer: C) 48 Explanation: No. of students will be 98 x 12 = 1176let us consider n circles then 1 + 2 + 3 + ....+ n = 1176n(n+1)/2 = 1176n = 48 circles.
Q: Find by how much percentage the average of first 10 odd numbers (starting from 1) is greater than the last term ? 1253 05b5cc71ee4d2b4197774f56d
5b5cc71ee4d2b4197774f56d- 1991/16 %false
- 2900/19 %true
- 3874/13 %false
- 4719/17 %false
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Answer : 2. "900/19 %"
Explanation :
Answer: B) 900/19 % Explanation: First ten odd numbers form an arithmetic progression of the form1,3,5,7,9......here a = first term = 1d = common difference = 2Average of first n numbers = (2a + (n - 1)d)/2n th term of the AP = a + (n - 1)dSubstituting a = 1, d = 2 and n = 10 in the above formulas average of first 10 numbers = 1010 th term of the AP = 19Therefore average of first 10 terms is 19 - 10 = 9 greater thanthe last term. Hence the average is greater than the sum by9/19 X 100 = 900/19 %
Q: In a cinema hall for the matinee show which started at 2.30 pm and ended at 5.30 pm the vehicle parking lot had only three wheelers (auto rickshaws) and four wheelers. Today the wheels of the vehicles parked was counted and found to be 240. What could be the number of three wheelers parked therein ? 2867 05b5cc71ee4d2b4197774f572
5b5cc71ee4d2b4197774f572- 148true
- 241false
- 345false
- 443false
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Answer : 1. "48"
Explanation :
Answer: A) 48 Explanation: 3X + 4y = 240by substitute through options 48 is correct
Q: Tanks A and B are each in the shape of a right circular cylinder. The interior of tank A has a height of 10 meters and a circumference of 8 meters, and the interior of tank B has a height of 8 meters and a circumference of 10 meters. The capacity of tank A is what percent of the capacity of tank B ? 1554 05b5cc71ee4d2b4197774f568
5b5cc71ee4d2b4197774f568- 176%false
- 272%false
- 380%true
- 482%false
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Answer : 3. "80%"
Explanation :
Answer: C) 80% Explanation: circumference of A = 2πr = 8 => so r = 4πvolume = π×4π2×10 = 160πcircumference of B = 2πr = 10 => so r = 5πvolume = π×5π2×8 = 200πso ratio of capacities = 160/200 = 0.8 so capacity of A will be 80% of the capacity of B.