Need help on this question. Thank you so much,

A given type of mixture gives a reverse phase separation that is okay, but not optimal using a combination of 70% acetonitrile and 30% water. You read a journal article that suggests that replacing acetonitrile with tetrahydrofuran (THF) will provide a better separation. Because you dont want the separation to take any longer to complete than it already does, you decide to keep the capacity factor for the longest-retained component the same for the separation in THF/Water as for the separation in cetonitrile/water. The capacity factor, k, for the longest retained component when acetonitrile/water is used is 10. What volume percentages of water and THF do you need to keep it that way? (Dont forget that the total volume fraction for THF plus water equals 1. Assume that the equilibration constant, KD, is the same for the last retained solute in both the acetonitrile/water and the THF/water mixtures.)