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  • Question
  • Find the number of diagonals formed in hexagon .


  • Options
  • A. 12
  • B. 10
  • C. 6
  • D. 9

  • Correct Answer


  • Explanation

    Hexagon has 6 sides .
    ? n = 6
    ? Required number of diagonals = 10C2 - n
    = 6C2 - 6
    = 6! / [2!(6 - 2)!] - 6 = 6! / (2!4!) - 6
    = (6 x 5 x 4!) / (2 x 4!) - 6
    = 15 - 6
    = 9


  • Permutation and Combination problems


    Search Results


    • 1. 
      There is a polygon of 12 sides . How many triangles can be drawn using the vertices of polygon?

    • Options
    • A. 200
    • B. 220
    • C. 240
    • D. 260
    • Discuss
    • 2. 
      In how many ways, a cricket team of 11 players can be made from 15 players, if a particulars player is always chosen?

    • Options
    • A. 1835
    • B. 1001
    • C. 1635
    • D. 1365
    • Discuss
    • 3. 
      In how many ways, a committee of 3 men and 2 women can be formed out of a total of 4 men and 4 women?

    • Options
    • A. 15
    • B. 16
    • C. 20
    • D. 24
    • Discuss
    • 4. 
      How many necklaces of 12 beads can be made from 18 beads of various colours?

    • Options
    • A. [118 x 13!] / 2
    • B. [110 x 14! ] / 2
    • C. [119 x 13!] / 2
    • D. [110 x 12!] / 2
    • Discuss
    • 5. 
      In how many different ways, 5 boys and 5 girls can sit on a circular table, so that the boys and girls are alternate?

    • Options
    • A. 2880
    • B. 2800
    • C. 2680
    • D. 2280
    • Discuss
    • 6. 
      There are 10 points in a plan, out of which 5 are collinear. Find the number of straight lines formed by joining them.

    • Options
    • A. 36
    • B. 45
    • C. 30
    • D. 35
    • Discuss
    • 7. 
      In how many ways, 12 balls can be divided between 2 boys, one receiving 5 and the other 7 balls?

    • Options
    • A. 1784
    • B. 1584
    • C. 1854
    • D. 1560
    • Discuss
    • 8. 
      Find the number of combinations that can be formed with 5 oranges, 4 mangoes and 3 bananas, when one fruit of each kind is taken.

    • Options
    • A. 60
    • B. 120
    • C. 110
    • D. 75
    • Discuss
    • 9. 
      There are 10 questions in a question paper. In how many ways, a student can solve there questions, if he solves one or more question?

    • Options
    • A. 1024
    • B. 1025
    • C. 1023
    • D. 1000
    • Discuss
    • 10. 
      In how many ways, can 15 people be seated around two round tables with seating capacities of 7 and 8 people?

    • Options
    • A. 15!/(8!)
    • B. 7!/88!
    • C. 15C8 x 6! x 7!
    • D. 15C8 x 8!
    • Discuss


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