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  • Question
  • A box contains 100 balls, numbered from 1 to 100. If three balls are selected at random and with replacement from the box, what is the probability that the sum of the three numbers on the balls selected from the box will be odd?


  • Options
  • A. 1/6
  • B. 1/3
  • C. 1/2
  • D. 1/4

  • Correct Answer
  • 1/2 

    Explanation

    P(odd) = P (even) = 1 2 1(because there are 50 odd and 50 even numbers)

     

    Sum or the three numbers can be odd only under the following 4 scenarios:

     

    Odd + Odd + Odd =  1 2 * 1 2 * 1 2 1 8

     

    Odd + Even + Even =  1 2 * 1 2 * 1 2 = 1 8

     

    Even + Odd + Even =  1 2 * 1 2 * 1 2 = 1 8

     

    Even + Even + Odd =  1 2 * 1 2 * 1 2  =  1 8

     

    Other combinations of odd and even will give even numbers. 

     

    Adding up the 4 scenarios above:

     

    1 8 1 8 + 1 8 1 8  =  4 8  =  1 2


  • More questions

    • 1. 
      The median for the data 2, 4, 6, 8, 10, 12, 14 is

    • Options
    • A. 6
    • B. 8
    • C. 9.5
    • D. 10
    • Discuss
    • 2. 
      The value of 47 / 10000 is?

    • Options
    • A. .0047
    • B. .0470
    • C. .00047
    • D. .000047
    • Discuss
    • 3. If 4x = 18y, then the value of ( x/y - 1) is

    • Options
    • A. 1 3
    • B. 7 2
    • C. 2 3
    • D. 3 2
    • Discuss
    • 4. 
      If the price of 23 toys is Rs. 276, then what will the price (Rs.) of 12 toys?

    • Options
    • A. 144
    • B. 158
    • C. 159
    • D. 166
    • Discuss
    • 5. 
      .02 =(......?.....)%

    • Options
    • A. 20
    • B. 2
    • C. .02
    • D. .2
    • Discuss
    • 6. 
      If 36 men can do a piece of work in 25 hours, in how many hours will 15 men do it?

    • Options
    • A. 45
    • B. 55
    • C. 60
    • D. 72
    • Discuss
    • 7. 
      2?63 / 11 =233

    • Options
    • A. 4
    • B. 3
    • C. 6
    • D. 5
    • Discuss
    • 8. 
      When 121012 is divided by 12, the remainder is

    • Options
    • A. 0
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 9. 
      Aarti can do a piece of work in 6 days. In how many days will she complete three time of work of same type?

    • Options
    • A. 18 days
    • B. 21 days
    • C. 3 days
    • D. 6 days
    • Discuss
    • 10. 
      750.0003 ÷ 19.999 =?

    • Options
    • A. 49
    • B. 18
    • C. 22
    • D. 38
    • Discuss


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