Probability · JEE Main previous year questions

2012 2 questions

1. Q212012 · 26 May 2012 · Shift 1

   There are two balls in an urn. Each ball can be either white or black. If a white ball is put into the urn and there after a ball is drawn at random from the urn, then the probability that it is white is

   1. A.$\frac{1}{4}$
   2. B.$\frac{2}{3}$
   3. C.$\frac{1}{5}$
   4. D.$\frac{1}{3}$
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   Answer: B

2. Q222012 · 12 May 2012 · Shift 1

   A number $n$ is randomly selected from the set $\{1,2,3,\dots ,1000\}$. The probability that $\frac{{\sum }_{i=1}^n{i}^2}{{\sum }_{i=1}^{n}i}$ is an integer is

   1. A.$0.331$
   2. B.$0.333$
   3. C.$0.334$
   4. D.$0.332$
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   Answer: C