IIT JEE Practice Question and Answer
8Q: You drive to the store at 20 kmph and return by the same route at 30 kmph. Discounting the time spent at the store, what was your average speed ? 1297 05b5cc745e4d2b4197774fa4a
5b5cc745e4d2b4197774fa4a- 125 kmphfalse
- 224 kmphtrue
- 326 kmphfalse
- 422 kmphfalse
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Answer : 2. "24 kmph"
Explanation :
Answer: B) 24 kmph Explanation: Average speed=total distance/total timeLet distance to store be Kthen, total time =(K/20)+(K/30)=K/12and, total time =(2K)so average speed= 2K / (K/12) = 24kmph.
Q: Maheshwari wants to buy 7 floors in an 68 storied building whose numbering stars from 1 upto 68. But she has to follow certain rules which are as follows : 1) None of the floor should be a prime number 2) None of the digit of the floor should be a prime number 3) Maheshwari cannot buy the 1st floor as it is being assigned to the architect. So how many options are left with Maheshwari to buy the floors ? 1296 05b5cc709e4d2b4197774f2a8
5b5cc709e4d2b4197774f2a8- 111false
- 217true
- 313false
- 419false
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Answer : 2. "17"
Explanation :
Answer: B) 17 Explanation: Since floor starts form the 1 therefore 2 will be the 1st floor.Form 1 to 10 only 4,6,8,9,10 are not prime.Form 11 to 20 only 14 ,16,18 are not prime also non of their digits are prime.From 21 to 30 each number has a prime number so it must no be consider.In between 40 to 49 we have to consider only 40,44,46,48,49.50 to 59 follow either of the condition so we have too neglect it.In between 60 to 68 60,64,66,68.total option = 17.
Q: What will come in place of the question mark (?) in the following question ? 52.5% of 800 + 30.5% of 2800 = ? + 87.30 1295 05b5cc6c1e4d2b4197774db2d
5b5cc6c1e4d2b4197774db2d- 11096.30false
- 21226.70false
- 31124.20false
- 41186.70true
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Answer : 4. "1186.70"
Explanation :
Answer: D) 1186.70 Explanation: 52.5% of 800 + 30.5% of 2800 = ? + 87.30 420 + 854 - 87.30 = ? 1274 - 87.30 = ? ? = 1186.70
Q: World’s highest railway bridge will be constructed on which river ? 1294 05b5cc6e3e4d2b4197774ecbb
5b5cc6e3e4d2b4197774ecbb- 1Gangafalse
- 2Chenabtrue
- 3Yamunafalse
- 4Kaverifalse
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Answer : 2. "Chenab"
Explanation :
Answer: B) Chenab Explanation: Chenab River in Jammu & Kashmir in next 2 years. Its height is 359 mts i.e 35mts more than the height of Eiffel Tower.
Q: Order of basicity of amines in gaseous state? 1294 05b5cc67ee4d2b4197774c274
5b5cc67ee4d2b4197774c274- 12'> 1'> 3' > NH3false
- 23' > 2' > 1'> NH3true
- 31' > 2' > 3'> NH3false
- 42'> 3'> 1' > NH3false
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Answer : 2. "3' > 2' > 1'> NH3"
Explanation :
Answer: B) 3' > 2' > 1'> NH3 Explanation: The order of basicity in ammonia is different in gaseous phases vs. aqueous phases due to hydrogen bonding. So in gaseous phases it's the well known: 3' > 2' > 1'> NH3. Just so we're on the same page, this is due to the inductive effect of electron donating alkyl groups--they destabilize the lone pair on nitrogen atom, making nitrogen more basic. But in aqueous phase, the order is slightly different: 2'> 1'> 3' > NH3.
Q: A container contains 120 lit of Diesel. From this container, 12 lit of Diesel was taken out and replaced by kerosene. This process was further repeated for two times. How much diesel is now there in the container ? 1294 05b5cc6c3e4d2b4197774dc86
5b5cc6c3e4d2b4197774dc86- 188.01 litfalse
- 287.48 littrue
- 387.51 litfalse
- 487.62 litfalse
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Answer : 2. "87.48 lit"
Explanation :
Answer: B) 87.48 lit Explanation: For these type of problems, Quantity of Diesel remained = q1-pqn Here p = 12 , q = 120 => 1201-121203 = 120 x 0.9 x 0.9 x 0.9 = 87.48 lit.
Q: State-run Bharat Sanchar Nigam (BSNL) unveiled its mobile wallet in partnership with _______ to enable one-tap bill payment for its over 100 million subscribers. 1293 05b5cc6cae4d2b4197774e090
5b5cc6cae4d2b4197774e090- 1Free Chargefalse
- 2MobiWiktrue
- 3Paytmfalse
- 4Ezetapfalse
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Answer : 2. "MobiWik"
Explanation :
Answer: B) MobiWik Explanation:
Q: Two parallel chords on the same side of the centre of a circle are 5 cm apart. If the chords are 20 and 28 cm long, what is the radius of the circle? 1293 05b5cc73ae4d2b4197774f8f7
5b5cc73ae4d2b4197774f8f7- 114.69 cmfalse
- 215.69 cmtrue
- 318.65 cmfalse
- 416.42 cmfalse
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Answer : 2. "15.69 cm"
Explanation :
Answer: B) 15.69 cm Explanation: Draw the two chords as shown in the figure. Let O be the center of the circle. Draw OC perpendicular to both chords. That divides the two chords in half.So CD = 10 and AB = 14. Draw radii OA and OD, both equal to radius r.We are given that BC = 5, the distance between the two chords. LetOB = x. We use the Pythagorean theorem on right triangle ABO AO² = AB² + OB² r² = 14² + x² We use the Pythagorean theorem on right triangle DCO DO² = CD² + OC² We see that OC = OB+BC = x+5, so r² = 10² + (x+5)² So we have a system of two equations: r² = 14² + x² r² = 10² + (x+5)² Since both left sides equal r², set the right sidesequal to each other. 14² + x² = 10² + (x+5)² 196 + x² = 100 + x² + 10x + 25 196 = 125 + 10x 71 = 10x 7.1 = x r² = 14² + x² r² = 196 + (7.1)² r² = 196 + 50.41 r² = 246.41 r = √246.41 r = 15.69745202 cm