How do I calculate total revenue with an increase or decrease in price?  Known factors are price elasticity of demand, income elasticity, and cross-price elasticity.

When the price of a good rises from $20 per unit to $30 per unit,the revenue of the firm producing this good rises from $100 to$300 calculate the price elasticity of supply

How would you expect the elasticity of demand for each of the following products to compare with the price elasticity of demand for standard car tires? Explain your answer. a. Snow tires (not necessary, but handy on snowy days) b. School bus tires (purchased with tax dollars on a fixed schedule) c. Bicycle tires (which require a smaller portion of a consumer's income than car tires) d. Tires made by the most reputable company (more of a luxury than a necessity)

Question 2. Suppose that the price elasticity of demand for an ice cream cone is -1.9. If the local ice cream shop owner wants to increase total revenue, what would you recommend he or she do?