Sally and eric are the only people in an economy. sally buys 3 bottles of water when the price is $2 a bottle and 4 bottles of water when the price is $1 a bottle. eric buys 10 bottles of water when he price is $0.50 a bottle and 5 bottles of water when the price is $1 a bottle. in the market for water, the quantity demanded
at $1 a bottle is 4 bottles
increases as the price rises
at $2 a bottle is 8 bottles
increases as the price falls