Demand and Supply are two major key concepts of Economics. Major part of economics is reliant on these two variables . Let 's have a look at what these are . Subscribe us on YouTube- Crash Study Demand Demand can be defined as the amount of goods or services that the consumers are willing and are able to buy at a given price over a period of time . Demand solely can be affected by a number of factors. Price - Price is one of the main factors that affect both supply and demand . Before making a purchase, we never forget to check the price, because we have to fund that purchase using a scarce resource. Simply , when the price is high the demand is likely to be lowered and when the price is low the is likely to be high . We will further discuss about how the price affect demand and how will demand affect the price in the upcoming sessions along with demand curves. Income of the consumers - Same as price income also is a major determinant of demand.