Christy and Cindy are running together. Cindy thinks Christy runs a little slow, so she gives Christy a 1.5 km advantage. This means Cindy is at the starting point and Christy is 1.5 km in front. Cindy runs 0.22 km per minute and Christy runs 0.12 km per minute. How long will it take before Cindy catches up to Christy?