Two identical spheres are dropped into two different columns: one column contains a liquid of viscosity 0.5

Question:

Two identical spheres are dropped into two different columns: one column contains a liquid of viscosity 0.5 Pa·s, while the other contains a liquid of the same density but unknown viscosity. The sedimentation velocity in the second tube is 20% higher than the sedimentation velocity in the first tube. What is the viscosity of the second liquid?