4 DEC SS Q.21

0. Out of a total of 10 students, the average weight of 9 students is 60 kg. If the Weight of the 10 student is 9 kg more than the average weight of all the 10 students, then the weight of 10 student would be :

  • Option : C
  • Explanation : Let weight of 1Oth student = x kg
    Average weight of 9 students = 60 kg
    total weight of 9 students = 9 x 60 = 540 kg
    Now, Average weight of 10 students
    = (540 + x)/10
    According to the question,
    x - (540 + x)/10 = 9
    1Ox - 540 - x = 90
    9x = 90 + 540 = 630
    x = 630/9 = 70 kg
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