An increase in price will induce a decrease in the quantity demanded. Substitutes are goods that can be used in place of the primary good. The mathematical relationship between the price of the substitute and the demand for the good is positive. If the price of the substitute goes down the demand for the good in question goes down.The greater the desire to own a good the more likely you are to buy the good. There is a basic distinction between desire and demand. If a consumer believes that the price of the good will be higher in the future he is more likely to purchase the good now. If the consumer expects that her income will be higher in the future the consumer may buy the good now. In other words positive expectations about future income may encourage present consumption.. All facts and circumstances that a buyer finds relevant to his willingness or ability to buy goods can affect demand.:
A product within an industry is elastic due to the availability of substitutes, the industry itself tends to be inelastic. if there is an increase in price and no change in the amount of income available to spend on the good, there will be an elastic reaction in demand; demand will be sensitive to a change in price if there is no change in income.