logo

CuriousTab

CuriousTab

Discussion


Home Aptitude Probability See What Others Are Saying!
  • 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. 
      ?. x 4 ? 227 = 398
      ?. y 2 + 321 = 346

    • Options
    • A. 1
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 2. If 6th March, 2005 is Monday, what was the day of the week on 6th March, 2004?

    • Options
    • A. Sunday
    • B. Saturday
    • C. Tuesday
    • D. Wednesday
    • Discuss
    • 3. 1, 4, 9, 16, 23, 25, 36

    • Options
    • A. 9
    • B. 23
    • C. 25
    • D. 36
    • Discuss
    • 4. 
      A sum of money is to be divided equally among P, Q and R in the respective ratio of 5 : 6 : 7 and another sum of money is to be divided between S and T equally. If S got ? 2100 less than P, then how much amount did Q receive?

    • Options
    • A. ? 2500
    • B. ? 2000
    • C. ? 1500
    • D. Couldn't be determined
    • Discuss
    • 5. 
      If a : b = b : c, then ratio a 4 : b 4 is equal to

    • Options
    • A. ac : b2
    • B. a2 : c2
    • C. c2 : a2
    • D. b2 : ac
    • Discuss
    • 6. 
      A man covers half of his journey at 6 km/h and the remaining half at 3 km/h. Find his average speed.

    • Options
    • A. 3 km/h
    • B. 4 km/h
    • C. 4.5 km/h
    • D. 9 km/h
    • Discuss
    • 7. 
      A person can walk a certain distance and drive back in 6 h. He can also walk both ways in 10 h. How much time will he take to drive both ways?

    • Options
    • A. 2 h
    • B. 21/2 h
    • C. 51/2 h
    • D. 4 h
    • Discuss
    • 8. 
      Find the least number by which 175760 be devided to make it a perfect cube.

    • Options
    • A. 10
    • B. 20
    • C. 100
    • D. 5
    • Discuss
    • 9. 
      The roots of the equation x2 + px + q = 0 are equal if :

    • Options
    • A. p2 = 2q
    • B. p2 = 4q
    • C. p2 = - 4q
    • D. p2 = - 2q
    • Discuss
    • 10. 
      Two cubes have volumes in the ratio 1: 27, The ratio of their surface areas is?

    • Options
    • A. 1 : 3
    • B. 1 : 8
    • C. 1 : 9
    • D. 1 : 18
    • Discuss


    Comments

    There are no comments.

Enter a new Comment