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  • Question
  • There are 14 points in a plane, out of which 4 are collinear. Find the number of triangles made by these points .


  • Options
  • A. 364
  • B. 360
  • C. 368
  • D. 365

  • Correct Answer
  • 360 

    Explanation

    The required number of triangles = nC3 - mC3

    Here, n = 14, m = 4
    = 14C3 - 4C3
    = (14 x 13 x 12 x 11! ) / (3! x 11!) - 4! / (3! x 1!)
    = (14 x 13 x 12)/6 - 4/1
    = 14 x 26 - 4
    = 364 - 4
    = 360


  • Permutation and Combination problems


    Search Results


    • 1. 
      In how many ways, can 24 persons be seated around a circular table if there are is 13 seats?

    • Options
    • A. 24! / [13 x 11! ]
    • B. 22! / [14 x 12!]
    • C. 23! / [13 x 11!]
    • D. 24! / [12 x 12!]
    • Discuss
    • 2. 
      There is a 7-digit telephone number with all different digits. If the digit at extreme right and extreme left are 5 and 6 respectively, find how many such telephone number are possible?

    • Options
    • A. 120
    • B. 100000
    • C. 6720
    • D. 30240
    • Discuss
    • 3. 
      A mixed doubles tennis game is to be played between two teams ( each team consists of one male and one female). There are four married couples. No team is to consist of a husband and his wife. What is the maximum number of games that can be played?

    • Options
    • A. 12
    • B. 48
    • C. 36
    • D. 42
    • Discuss
    • 4. 
      In how many ways can the letters of the word 'Director' be arranged so that the three vowels are never together?

    • Options
    • A. 1800
    • B. 18000
    • C. 16000
    • D. 1600
    • Discuss
    • 5. 
      Vowels being never together.

    • Options
    • A. 36 ways
    • B. 84 ways
    • C. 120 ways
    • D. 10 ways
    • Discuss
    • 6. 
      A question paper consists of two sections having respectively 3 and 5 questions. The following note is given on the paper. "It is not necessary to attempt all the question". One question from each section is compulsory. In how many ways, a candidate can select the question?

    • Options
    • A. 38
    • B. 217
    • C. 256
    • D. 320
    • Discuss
    • 7. 
      There are 10 stations on a railway line. The number of different journey tickets that are required by the authorities, is

    • Options
    • A. 92
    • B. 90
    • C. 91
    • D. 93
    • Discuss
    • 8. 
      The number of ways in which a committee of 3 ladies and 4 gentlemen can be appointed from a group consisting of 8 ladies and 7 gentlemen, if Mrs. X refuses to serve in a committee if Mr. Y is its member, is

    • Options
    • A. 1960
    • B. 3240
    • C. 1540
    • D. None of these
    • Discuss
    • 9. 
      A five-digit number divisible by 3 is to be formed using digits 0, 1, 2, 3, 4 and 5 without repetition, the total number of ways this can be done, is

    • Options
    • A. 122
    • B. 210
    • C. 216
    • D. 217
    • Discuss
    • 10. 
      A new flag is to be designed with six vertical stripes using some or all of the colour yellow, green,blue and red. Then, the number of ways this can be made such that no two adjacent stripes have the same colour is

    • Options
    • A. 12 x 81
    • B. 16 x 192
    • C. 20 x 125
    • D. 24 x 216
    • Discuss


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