Define price elasticity of demand with its types.

The percentage change in quantity demanded of a commodity due to percentage change in price of that commodity is known as price elasticity of demand.

There are 5 types of price elasticity of demand.

        1.  Perfectly Elastic Demand:
                 When negligible change in price leads to infinite change in quantity demanded ,the demand for a commodity is said to be perfectly elastic demand. 

 ...

Explain the income elasticity of demand with example.

The proportionate change in quantity demanded for a goods due to the proportionate change in consumer's income is called income elasticity of demand. It is usually written as:  

There are three types of income elasticity:
1. Positive Income Elasticity : 
If increase in income leads to increase in demand of a commodity and decrease in income leads to decrease in demand of a commodity, it is called positive income elasticity. Positive income elasticity can be divided into...