Question

320ml of active ingredient is added to 680ml of an alcohol based solution. What is the final strength (v/v)? ___

Answer 1

Use your other posts as a template.
% v/v is mL solute/total mL and you assume the volumes are additive (which isn't the usual case).

Answer 2

I have posted correctly

Answer 3

320ml of active ingredient is added to 680 ml of an alcohol based solution. What is the final strength (v/v)?________