Affiliate Marketing Secrets

The local Chinese markets used to have something called Sea Coconut Cough Syrup, you can see the box here:
http://www.amaluxherbal.com/affiliated/african%20sea%20coconut%20cough%20syrup.htm
Since Fall of 2011 the markets have not had any, nor has anyone I have tried to ask known why, they just say it’s not coming in anymore. Anyone seen a report as to why? This was very effective so I would like to know why my favorite medicine is no longer available.
Thanks!

Homer Simpson wants to mass market his world famous Flmaing Moe cocktail made of tequila, schnapps, creme de menthe, plus the secret ingredient – Krusty’s Non Narkotik Kough Syrup for Kids. He starts by filling a tank with 80 liters of alcohol mix. Next, he pumps an alcohol solution containing 0.5 kg per liter of cough syrup into the tank at a steady rate of 4 liters per minute. The well-mixed solution leave the tank at the same rate.
A) Find the amount of cough syrp in the tank at any time t.
B) The drink tastes best when the cough syrup concentration is 0.2 kg/l. Find the time t when Homer can bottle a Flaming Moe Premium for his personal stash.
If anyone could explain how to arrive at the solution, I would greatly appreciate it!