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  • Question
  • How many 7 digit numbers can be formed using the digits 1, 2, 0, 2, 4, 2, 4?


  • Options
  • A. 120
  • B. 360
  • C. 240
  • D. 424

  • Correct Answer
  • 360 

    Explanation

    There are 7 digits 1, 2, 0, 2, 4, 2, 4 in which 2 occurs 3 times, 4 occurs 2 times.

     

     Number of 7 digit numbers =  7 ! 3 ! × 2 !  = 420

     

    But out of these 420 numbers, there are some numbers which begin with '0' and they are not 7-digit numbers. The number of such numbers beginning with '0'.

     

    = 6 ! 3 ! × 2 !  = 60

     

    Hence the required number of 7 digits numbers = 420 - 60 = 360

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

    More questions

    • 1. 
      A can complete a piece of work in 10 days, while B alone can complete it in 15 days. They work together for 5 days and rest of the work is done by C in 2 days. If they receive $ 450 for the whole work, how should they divide the money?

    • Options
    • A. $250, $100, $100
    • B. $225, $150, $75
    • C. $200, $150, $100
    • D. $175, $175, $100
    • Discuss
    • 2. 
      The angle of elevation of a tower from a distance 50 m from its foot is 30°. The height of the tower is :

    • Options
    • A. 50 ?3 m
    • B. 50 m ?3
    • C. 75 ?3 m
    • D. 75 m ?3
    • Discuss
    • 3. 
      If 30% of A = 20 % of B, then find the value of A : B?

    • Options
    • A. 1 : 3
    • B. 3 : 2
    • C. 3 : 1
    • D. 2 : 3
    • Discuss
    • 4. 80 litre mixture of milk and water contains 10% milk. How much milk (in litres) must be added to make water percentage in the mixture as 80%?

    • Options
    • A. 8
    • B. 9
    • C. 10
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    • 5. 
      If log 5 (x 2 + x) - log 5 x = 2 then the value of x is?

    • Options
    • A. 24
    • B. 25
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    • 6. The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?

    • Options
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    • 7. 
      Two trains A and B travel from points X to Y and the ratio of the speeds of A to that of B is 2 : 7. Find the ratio of time taken by A and B to reach From X to Y.

    • Options
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    • B. 3 : 5
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    • 8. 
      Walking with 3/4 of his usual speed, Sachin covers a certain distance in 2 h more than the time he takes to cover the distance at his usual speed. Find the time taken by him to cover this distance with usual speed.

    • Options
    • A. 5 h
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    • C. 9 h
    • D. 4 h
    • Discuss
    • 9. 
      If ? 2 n = 64, then the value of n is?

    • Options
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    • 10. 
      Ram and Sita are walking towards each other with the speed of 8 km/h and 2 km/h, respectively over a road 160 km long. How soon will they meet?

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