Normally when the price of a good is decreased, the demand for that good will go up because its consumers can afford to buy more of it. This can be shown graphically.
Figure 1.1: Figure 1.1 shows a graphical representation of the demand curve for Yorkie Bars. On the vertical axis Price (P) is represented. The Quantity (Q) is represented on the horizontal axis. At a price of 2 only 4 bars were sold. When this price was brought down to 1 the quantity demanded of it went up to 18. The demand curve is derived by plotting a line threw these two points.
Supply and its curve essentially have very similar characteristics to demand although supply slopes in the upwards direction. The supply curve tells us how much producers are willing to sell at each price they receive in the market. When demand and supply are represented on the same graph an economist can determine where the equilibrium price is and if the price being charged is leading to a market surplus or