Below are the scores of a group of students in a test (begin{array}{c|c} Scores &…

Below are the scores of a group of students in a test
(begin{array}{c|c} Scores & 1 & 2 & 3 & 4 & 5 & 6 \ hline text{No. of students} & 1 & 4 & 5 & 6 & x & 2end{array})
If the average scores is 3.5, find the value of x
  • A.
    1
  • B.
    2
  • C.
    3
  • D.
    4
Correct Answer: Option B
Explanation

(begin{array}{c|c} Scores & 1 & 2 & 3 & 4 & 5 & 6 \ hline text{No. of students} & 1 & 4 & 5 & 6 & x & 2end{array})
Average = 3.5
3.5 = (frac{(1 times 1) + (2 times 4) + (3 times 5) + (4 times 6) + 5x + (6 times 2)}{1 + 4 + 5 + 6 + x + 2})
(frac{3.5}{1}) = (frac{1 + 8 + 15 + 24 + 5x + 12}{18 + x})
(frac{3.5}{1}) = (frac{60 + 5x}{18 + x})
60 + 5x = 3.5(18 (div) x)
60 + 5x = = 63 + 1.5x
5x – 1.5x = 63 – 60
1.5x = 3
x = (frac{3}{1.5})
(frac{30}{15}) = 2

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