Hi, I need help with my Econo homework

Q1. At a farmers' market, the initial price for a cup of fresh fruit & veggie juice is $5.00, and the quantity demanded is 350 cups When the price is raised to $5.25, the quantity demanded falls to 300 cups What is the elasticity of demand?

Q2. The price elasticity for headphones has been estimated at -1.5. At the initial price of $20, the quantity demanded was 10 units/day. If the firm cuts the price to $17.50, quantity demanded is expected to increase by _____. a) 18.75% b) 6.67% c) 8.75% d) 10.33% e) 12.5%

Q3, A firm's demand curve is estimated to be Q = 400 - 5p At p = $15, what is the point elasticity of demand? 12

Q4. Consider a demand function Q = 100 - 4p. When elasticity is -2, what is the price?