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Home Aptitude Permutation and Combination See What Others Are Saying!
  • Question
  • Compute the sum of 4 digit numbers which can be formed with the four digits 1,3,5,7, if each digit is used only once in each arrangement.


  • Options
  • A. 105555
  • B. 106665
  • C. 106656
  • D. 108333

  • Correct Answer
  • 106656 

    Explanation

    The number of arrangements of 4 different digits taken 4 at a time is given by  4 P 4  = 4! = 24.All the four digits will occur equal number of times at each of the position,namely ones,tens,hundreds,thousands.

     

     

     

    Thus,each digit will occur 24/4 = 6 times in each of the position.The sum of digits in one's position will be 6 x (1+3+5+7) = 96.Similar is the case in ten's,hundred's and thousand's places.

     

     

     

    Therefore,the sum will be 96 + 96 x 10 + 96 x 100 + 96 x 100 = 106656


  • More questions

    • 1. 
      0.0169 / 0.013=?

    • Options
    • A. .13
    • B. .013
    • C. 1.3
    • D. 13
    • Discuss
    • 2. 
      Two posts are x meter apart and the height of one is double that of the other. If from the midpoint of the line joining their feet, an observer finds the angular elevations of their tops to be complementary, then the height (in meter) of the shorter post is :

    • Options
    • A. x 2 ?2
    • B. x 4
    • C. x ?2
    • D. x ?2
    • Discuss
    • 3. 
      If p/q =4/5, then the value of 4/7 + {(2q - p) / (2q + p)} is?

    • Options
    • A. 3 / 7
    • B. 34
    • C. 1
    • D. 2
    • Discuss
    • 4. 
      What is 25% of 25% is equal to?

    • Options
    • A. 6.25
    • B. .625
    • C. .0625
    • D. .000625
    • Discuss
    • 5. 
      The number .05 is hoe many percent of 20?

    • Options
    • A. 25
    • B. .025
    • C. .25
    • D. 2.5
    • Discuss
    • 6. Find the lowest common multiple of 24, 36 and 40.

    • Options
    • A. 120
    • B. 240
    • C. 360
    • D. 480
    • Discuss
    • 7. 
      8 1/ 3% expressed as a fraction is?

    • Options
    • A. 25/3
    • B. 3/25
    • C. 1/12
    • D. 1/4
    • Discuss
    • 8. 
      .025 in terms of term of rate per cent is?

    • Options
    • A. .25%
    • B. 2.5%
    • C. 0.25%
    • D. 371/2%
    • Discuss
    • 9. 
      What percentage of 2/7 is 1/35?

    • Options
    • A. 2.5%
    • B. 10%
    • C. 25%
    • D. 20%
    • Discuss
    • 10. 
      A sum of ? 4000 is lent out in two parts, one at 8% simple interest and other at 10% simple interest. If the annual interest is ? 352, the sum lent at 8% is

    • Options
    • A. ? 1600
    • B. ? 2400
    • C. ? 1800
    • D. ? 2800
    • Discuss


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