I attempted this question, and I'm kind of stuck on the first part. This is my attempt so far:

Vm = Flow rate x to(dead time) = 2.12x1.5 = 3.18
Vs = Phase ratio x Vo = 0.1(since its 10% of the column) x Vm(dead volume) = 0.318

I am certain my Vs is the wrong value, however I'm wondering how would you calculate the Vs value without the PArtition coefficient? And secondly, how would you answer part IV? Thanks

An HPLC column was found to have to = 2.12 min when operated at 1.50
mL min-1. Eight compounds are being separated with the first peak eluting
at 3.05 min, while the last eluted at 29.42 min. Given that the column was
20.0 cm long and 4.60 mm in diameter, and that the stationary phase
accounted for 10. 00% of the solid volume of the column
(i) Calculate VM and Vs for the column.
(ii) Using the values from part (a), calculate the range of K values for the
sample components
(iii) Assuming that N = 2.00 x 104, what are the baseline widths of the
first and last sample peaks?
(iv) Given that there are 8 sample components, by how much can the
analysis time be reduced (assume the first component is unretained)?