An item is called "price elastic" if you drop the price and revenue goes up. Last week you sold 10 sodas for $2 each; this week you sold 30 sodas for $1 each. Is soda price elastic?

The soda is price elastic because if you sell 10 dollars ecah you have an revenue of 20 dollars. And if you shorten the price to 1 dollar and you sell 30 of them you have a revenue of 30 dollars.

So the sodas are price elastic.