If the arithmetic mean of 1,2,3,4,5,6,x, 16 and 18 is 8.0, find the value of x?
- 7.0
- 6.0
- 8.5
-
17.0
The correct answer is: D
Explanation
8 x \(\frac{55 + x}{9}\)
cross multiply
9 x 8 = 55 + x
72 - 55 = 17
x = 17