It\textquotesingle s summer time! A beverage shop mixes $10$ bottles of apple and $20$ bottles of watermelon juice to make the new blended juice. The costs of a bottle of apple and a bottle of watermelon juice are $8$ and $11$ dollars, respectively. If the size of the bottle does not change, what is the cost of each bottle of the blended juice? 
Overseas Competition->Knowledge Point->Word Problem Modules->Average Problems 
Total cost: $$10\times 8+11\times 20=300$$.  There are $$10+20=30$$ bottles, so each bottle of the blended juice should be $$300\div 30=10$$ dollars. 