If you need 11 skeins of Kochoran, you need 11 x 176 yds of yarn, so 1936 yards in total.
At 110 yds per skein, you need 1936/110 =18 skeins of silk garden.
You can always add 1-2 skeins to make sure you don't run out.
As you can see, the price per skein is not a very good estimate since the yardage can differ greatly!
Noro makes beautiful yarns but it can be a bit pricey (and some people find their yarns scratchy). If you want to find something cheaper, keep the 1936 yards in mind and look at yarn with similar gauge. yarndex.com is a good place to look. Good luck!