Permutations & Combinations · JEE Main previous year questions

2012 3 questions

1. Q32012 · 26 May 2012 · Shift 1

   If seven women and seven men are to be seated around a circular table such that there is a man on either side of every woman, then the number of seating arrangements is

   1. A.$6!7!$
   2. B.$(6!{)}^2$
   3. C.$(7!{)}^2$
   4. D.$7!$
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   Answer: A

2. Q152012 · 26 May 2012 · Shift 1

   If a metallic circular plate of radius $50\mathrm{cm}$ is heated so that its radius increases at the rate of $1\mathrm{mm}$ per hour, then the rate at which, the area of the plate increases (in $\mathrm{c}{\mathrm{m}}^2/hour$) is

   1. A.$5\pi$
   2. B.$10\pi$
   3. C.$100\pi$
   4. D.$50\pi$
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   Answer: B

3. Q162012 · 7 May 2012 · Shift 1

   If a circular iron sheet of radius $30\mathrm{cm}$ is heated such that its area increases at the uniform rate of $6\pi \mathrm{c}{\mathrm{m}}^2/hr$, then the rate (in $mm/hr$) at which the radius of the circular sheet increases is

   1. A.1.0
   2. B.0.1
   3. C.1.1
   4. D.2.0
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   Answer: A