Mathematics

The table above shows that the scores of a group of students in a test….

The table above shows that the scores of a group of students in a test. If the average score is 3.5, find the value of x
  • A.
    1
  • B.
    2
  • C.
    3
  • D.
    4
Correct Answer: Option B
Explanation

(mean=frac{60+5x}{18+x}\3.5=frac{60+5x}{18+x}\frac{7}{2}=frac{60+5x}{18+x})
7(18+x) = 2(60+5x)
126 + 7x = 120 + 10x
10x – 7x = 126 – 120
3x = 6
x = 2