IIT JEE Practice Question and Answer
8Q: A single pipe of diameter x has to be replaced by six pipes of diameters 12 cm each. The pipes are used to covey some liquid in a laboratory. If the speed/flow of the liquid is maintained the same then the value of x is ? 1507 05b5cc73ae4d2b4197774f902
5b5cc73ae4d2b4197774f902- 114.69 cmfalse
- 229.39 cmtrue
- 318.65 cmfalse
- 422.21 cmfalse
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Answer : 2. "29.39 cm"
Explanation :
Answer: B) 29.39 cm Explanation: Volume of water flowing through 1 pipe of diameter x = Volume discharged by 6 pipes of diameter 12 cms. As speed is same, area of cross sections should be same. Area of bigger pipe of diameter x = Total area of 6 smaller pipes of diameter 12 i.e πR2 = 6πR12 Here R = R and R1 = 12/2 = 6 ⇒R2 = 6×6×6 R = 14.696 => D = X = 14.696 * 2 = 29.3938 cm.
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? 973 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
Q: Population of a colony of mosquitoes is increasing by 20% per day. If the population on Monday was 3000, on which day of that week the population would be 5184 ? 1453 05b5cc73ae4d2b4197774f8f1
5b5cc73ae4d2b4197774f8f1- 1Thursdaytrue
- 2Fridayfalse
- 3Tuesdayfalse
- 4Mondayfalse
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Answer : 1. "Thursday"
Explanation :
Answer: A) Thursday Explanation: Given monday population = 3000Per day 20% increase in population. Tuesday population = 3000 + 3000x20/100 = 3000 + 600 = 3600 Wednesday population =3600 + 3600x20/100 = 3600 + 720 = 4320 Thursday population = 4320 + 4320x20/100 = 4320 + 864 = 5184 So that day is Thursday.
Q: An express train takes 4 seconds to enter tunnel which is 1 km long. If it is traveling at 108 km an hour, how long will it take to pass completely through the tunnel ? 1303 05b5cc73ae4d2b4197774f8ec
5b5cc73ae4d2b4197774f8ec- 133 secfalse
- 237.33 sectrue
- 336.43 secfalse
- 432 secfalse
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Answer : 2. "37.33 sec"
Explanation :
Answer: B) 37.33 sec Explanation: Speed = 108 km/hrenter a tunnel,, means that the train covers a distance equal to its own lengthso (108 x 5/18) = x/4 where x= length of trainhence x = 120 mtrsto pass completely train has to travel a distance = (x + tunnel length) that is 1120 mtrs.so (1120/t) = (108x5/18)t = 37.33 sec
Q: The market was full of people ……….. attractive clothes of different styles. 42962 05b5cc73ae4d2b4197774f8e2
5b5cc73ae4d2b4197774f8e2- 1showingfalse
- 2watchingfalse
- 3Havingfalse
- 4wearingtrue
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Answer : 4. "wearing"
Explanation :
Answer: D) wearing Explanation: The market was full of people wearing attractive clothes of different styles.
Q: Three strategies P, Q and R have been initiated for cost cutting in a company producing respectively 20%, 30% and 10% savings. Assuming that they operate independently, what is the net saving achieved ? 1694 05b5cc73ae4d2b4197774f8dd
5b5cc73ae4d2b4197774f8dd- 149.6%true
- 250.4%false
- 333.67%false
- 466.66%false
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Answer : 1. "49.6%"
Explanation :
Answer: A) 49.6% Explanation: As these three strategies P, Q and R are independent so these will cut cost one after the other.If initial cost is Rs 100, then20% cost is cut after initializing strategy P, then cost will remain 80% = 80further 30% cost is cut after strategy Q, then cost will remain 70% of 80 = 56further 10% cost is cut after strategy R, then cost will remain 90% of 56 = 50.4 Thus final cost remains 50.4 % of the original cost. Hence net saving is 100 - 50.4 = 49.6 %.
Q: A group of men can complete a job in K hours. After every 4 hours, half the number of men working at that point of time leave the job. Continuing this way if the job is finished in 16 hours, what is the value of K ? 3359 05b5cc73ae4d2b4197774f8d8
5b5cc73ae4d2b4197774f8d8- 17 hrsfalse
- 27.5 hrstrue
- 38 hrsfalse
- 48.25 hrsfalse
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Answer : 2. "7.5 hrs"
Explanation :
Answer: B) 7.5 hrs Explanation: Let there are L men job requires LK man hours. job completed in first 4 hrs = L x 4 = 4L job completed in next 4 hrs = 4 x L/2 = 2L job completed in next 4 hrs = 4 x L/4 = L job completed in last 4 hrs = 4 x L/8 = L/2 4L + 2L + L + L/2 = KL K = 7+1/2 = 7.5 hours.
Q: 5 years ago Sushma was 5 times as old as her Son. 5 years hence her age will be 8 less than three times the corresponding age of her Son. Find their ages ? 2958 05b5cc73ae4d2b4197774f8d3
5b5cc73ae4d2b4197774f8d3- 124 and 13 yearsfalse
- 248 and 24 yearsfalse
- 335 and 11 yearstrue
- 433 and 15 yearsfalse
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Answer : 3. "35 and 11 years"
Explanation :
Answer: C) 35 and 11 years Explanation: Let the age of sushma be x and the age of her son is yThen five years before x-5=5(y-5) ...(1)Five years hence x+5 = 3(y+5)-8 .....(2) By soving (1) & (2), we get5y - 15 = 3y + 7y = 11 => x = 35 Therefore, the age of Sushma = 35 and her son = 11.