Plain : Spotted : Striped socks are in the ratio of 5 : 3 : 8
So we can say that number of plain socks = 5x
Number of spotted socks = 3x
Number of striped socks = 8x
Hence, total number of socks = 5x + 3x + 8x = 16x
⇒ Fraction of Striped Socks =

⇒ Fraction of Striped Socks =

⇒ Fraction of Striped Socks =

Hence,
of Alex's socks are striped