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  • Question
  • A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If two marbles are picked at random, what is the probability that they are either blue or yellow ?


  • Options
  • A. 3/17
  • B. 4/21
  • C. 2/21
  • D. 5/17

  • Correct Answer
  • 2/21 

    Explanation

    Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.

     

    Probability that both marbles are blue = ³C?/¹?C? = (3 x 2)/(15 x 14) = 1/35

    Probability that both are yellow = ²C?/¹?C? = (2 x 1)/(15 x 14) = 1/105

    Probability that one blue and other is yellow = (³C? x ²C?)/¹?C? = (2 x 3 x 2)/(15 x 14) = 2/35

     

    Required probability = 1/35 + 1/105 + 2/35 = 3/35 + 1/105 = 1/35(3 + 1/3) = 10/(3 x 35) = 2/21

  • Tags: GATE, CAT, Bank Exams, AIEEE, Bank PO, Bank Clerk

    Permutation and Combination problems


    Search Results


    • 1. If (1 × 2 × 3 × 4 ........ × n) = n!, then 15! - 14! - 13! is equal to ___?

    • Options
    • A. 14 × 13 × 13!
    • B. 15 × 14 × 14!
    • C. 14 × 12 × 12!
    • D. 15 × 13 × 13!
    • Discuss
    • 2. How many words can be formed with or without meaning by using three letters out of k, l, m, n, o without repetition of alphabets.

    • Options
    • A. 60
    • B. 120
    • C. 240
    • D. 30
    • Discuss
    • 3. How many ways can 10 letters be posted in 5 post boxes, if each of the post boxes can take more than 10 letters ?

    • Options
    • A. 5^10
    • B. 10^5
    • C. 5P5
    • D. 5C5
    • Discuss
    • 4. Consider the word ROTOR. Whichever way you read it, from left to right or from right to left, you get the same word. Such a word is known as palindrome. Find the maximum possible number of 5-letter palindromes.

    • Options
    • A. 17756
    • B. 17576
    • C. 12657
    • D. 12666
    • Discuss
    • 5. In how many different ways can the letters of the word 'DETAIL' be arranged in such a way that the vowels occupy only the odd positions?

    • Options
    • A. 36
    • B. 25
    • C. 42
    • D. 120
    • Discuss
    • 6. There are 11 True or False questions. How many ways can these be answered ?

    • Options
    • A. 11!/2
    • B. 1024
    • C. 11!
    • D. 2048
    • Discuss
    • 7. If each vowel of the word NICELY is changed to the next letter in the English alphabetical series and each consonant is changed to the previous letter in the English alphabetical series and then the alphabets are arranged in alphabetical order, which of the following will be fourth from the left?

    • Options
    • A. M
    • B. J
    • C. B
    • D. O
    • Discuss
    • 8. The ratio of the members of blue to red balls in abag is constant. When there were 44 red balls, the number of blue balls was 36. If the number of blue balls is 54, how many red balls will be in the bag?

    • Options
    • A. 68
    • B. 32
    • C. 64
    • D. 66
    • Discuss
    • 9. How many more words can be formed by using the letters of the given word 'CREATIVITY'?

    • Options
    • A. 851250
    • B. 751210
    • C. 362880
    • D. 907200
    • Discuss
    • 10. A box contains 5 green, 4 yellow and 5 white pearls. Four pearls are drawn at random. What is the probability that they are not of the same colour ? A) 11/91 B) 4/11 C) 1/11 D) 90/91

    • Options
    • A. Option A
    • B. Option B
    • C. Option C
    • D. Option D
    • Discuss


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