CSIR NET
   Top Resources
profile-img
Eduncle posted an MCQ
October 20, 2019 • 15:50 pm 0 points
  • CSIR NET
  • Life Sciences

12 balls, 3 each of the colours red, green, blue and yellow are put in a box and mixed. If 3 balls are picked at random,

12 balls, 3 each of the colours red, green, blue and yellow are put in a box and mixed. If 3 balls are picked at random, without replacement, the probability that all 3 balls are of the same colour is

Choose Your Answer:
0 Attempts Submit Now
  • 0 Likes
  • 1 Comments
  • 0 Shares
  • comment-profile-img>
    Eduncle Best Answer

    The probability that 1st ball is of 1 colour = 3/12 
    2nd ball also of same colour without replacement = 2/11
    3rd ball of same colour without replacement = 1/10
    Total probability = P (A & B & C) 3/12 × 2/11 × 1/10 = 6/1320
    Since there are 3 others colours (each having same no. of balls mixed). All of the individual probabilities need to be added up . The reason this has to be done is because they have not mentioned any particular colour of ball to be picked.
    i.e 6/1320 + 6/1320 + 6/1320 + 6/1320 = 24/1320 = 1/55 Ans.

whatsapp-btn

Do You Want Better RANK in Your Exam?

Start Your Preparations with Eduncle’s FREE Study Material

  • Updated Syllabus, Paper Pattern & Full Exam Details
  • Sample Theory of Most Important Topic
  • Model Test Paper with Detailed Solutions
  • Last 5 Years Question Papers & Answers

Sign Up to Download FREE Study Material Worth Rs. 500/-