IIT JEE Practice Question and Answer
8Q: A certain sum of money is invested for one year at a certain rate of simple interest. If the rate of interest is 3% higher, then the invest earned will be 25% more than the interest earned earlier. What is the earlier rate of interest ? 2441 05b5cc6eee4d2b4197774eeeb
5b5cc6eee4d2b4197774eeeb- 14% p.a.false
- 26% p.a.false
- 38% p.a.false
- 412% p.a.true
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Answer : 4. "12% p.a."
Explanation :
Answer: D) 12% p.a. Explanation: If the interest earned is 25% more than the earlier interest then the rate of interest also should be 25% higher than the earlier rate. Let the earlier rate of interest be x%. Now it will be (x + 3)% % increase = (x + 3) - x/x * 100 = 25=> x = 12%
Q: A group of 10 representatives is to be selected out of 12 seniors and 10 juniors. In how many different ways can the group be selected if it should have at least one senior ? 5799 05b5cc6eee4d2b4197774eed7
5b5cc6eee4d2b4197774eed7- 1²²C₁₀ + 1false
- 2²²C₉ + ¹⁰C₁false
- 3²²C₁₀false
- 4²²C₁₀ - 1true
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Answer : 4. "²²C₁₀ - 1"
Explanation :
Answer: D) ²²C₁₀ - 1 Explanation: The total number of ways of forming the group of ten representatives is ²²C₁₀. The total number of ways of forming the group that consists of no seniors is ¹⁰C₁₀ = 1 way The required number of ways = ²²C₁₀ - 1
Q: Find the least number with which 16200 should be multiplied, to make it a perfect cube ? 2556 05b5cc6eee4d2b4197774eec3
5b5cc6eee4d2b4197774eec3- 145true
- 248false
- 3360false
- 436false
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Answer : 1. "45"
Explanation :
Answer: A) 45 Explanation: 16200 = 23×34×52 A perfect cube has a property of having the indices of all its prime factors divisible by 3. Required number = 32×5 = 9x5 = 45.
Q: A person takes 20 minutes more to cover a certain distance by decreasing his speed by 20%. What is the time taken to cover the distance at his original speed ? 5506 05b5cc6eee4d2b4197774eebe
5b5cc6eee4d2b4197774eebe- 11hrfalse
- 21 hr 20 mintrue
- 31 hr 10 minfalse
- 450 minfalse
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Answer : 2. "1 hr 20 min"
Explanation :
Answer: B) 1 hr 20 min Explanation: Let the distance and original speed be 'd' km and 'k' kmph respectively. d/0.8k - d/k = 20/60 => 5d/4k - d/k = 1/3 => (5d - 4d)/4k = 1/3 => d = 4/3 k Time taken to cover the distance at original speed = d/k = 4/3 hours = 1 hour 20 minutes.
Q: A cistern has a leak which would empty the cistern in 20 minutes. A tap is turned on which admits 4 liters a minute into the cistern, and it is emptied in 24 minutes. How many liters does the cistern hold ? 7114 05b5cc6ebe4d2b4197774eeb4
5b5cc6ebe4d2b4197774eeb4- 1360 litfalse
- 2480 littrue
- 3320 litfalse
- 4420 litfalse
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Answer : 2. "480 lit"
Explanation :
Answer: B) 480 lit Explanation: 1/k - 1/20 = -1/24 k = 120 120 x 4 = 480 Therefore, the capacity of the cistern is 480 liters.
Q: Compound interest earned on a sum for the second and the third years are Rs.1200 and Rs.1440 respectively. Find the rate of interest ? 3091 05b5cc6ebe4d2b4197774eeb9
5b5cc6ebe4d2b4197774eeb9- 120% p.atrue
- 215% p.afalse
- 318% p.afalse
- 424% p.afalse
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Answer : 1. "20% p.a"
Explanation :
Answer: A) 20% p.a Explanation: Rs.1440 - 1200 = Rs.240 is the interest on Rs.1200 for one year. Rate of interest = (100 x 240) / (1200) = 20% p.a
Q: Divide Rs.118000 among three persons A, B and C such that the ratio of the shares of A and B is 3:4 and that of B:C is 5:6 ? 3218 05b5cc6ebe4d2b4197774eeaa
5b5cc6ebe4d2b4197774eeaa- 1A = 48000 B = 40000 C = 30000false
- 2A = 30000 B = 40000 C = 48000true
- 3A = 30000 B = 48000 C = 40000false
- 4A = 40000 B = 48000 C = 30000false
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Answer : 2. "A = 30000 B = 40000 C = 48000"
Explanation :
Answer: B) A = 30000 B = 40000 C = 48000 Explanation: Compound ratio of A:B:CA:B = 3:4B:C = 5:6----------A:B:C = 15:20:24 We can divide Rs.118000 in this ratio. Share of A = 15/59 x 118000 = 30000 Share of B = 20/59 x 118000 = 40000 Share of C = 24/59 x 118000 = 48000
Q: Find the one which does not belong to that group ? 4581 05b5cc6ebe4d2b4197774eeaf
5b5cc6ebe4d2b4197774eeaf- 1KMNLfalse
- 2JLMKfalse
- 3PRSQfalse
- 4VWYZtrue
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Answer : 4. "VWYZ"
Explanation :
Answer: D) VWYZ Explanation: K+2 M+1 N-2 L, P+2 R+1 S-2 Q, V+1 W+2 Y+1 Z, J+2 L+1 M-2 K and W+2 Y+1 Z-2 X. Except VWYZ, all the other groups follow similar pattern.