Milk and cream contain different percents of butterfat. How much 3% milk needs to be mixed with how much 15% cream to give 20L or 6% cream? Show all of your work and write out your steps in words.

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?