JAMB - Economics (2001 - No. 12)
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
Explication
8 x \(\frac{55 + x}{9}\)
cross multiply
9 x 8 = 55 + x
72 - 55 = 17
x = 17
8 x \(\frac{55 + x}{9}\)
cross multiply
9 x 8 = 55 + x
72 - 55 = 17
x = 17