Hi! I need explanation how to solve this. I stuck at this questions,

DIFFERENTIATION AND COMPARATIVE STATICS

Suppose that the demand for a product is given ()=600.

a) Find the elasticity of demand at =20

b) Tell what type of elasticity this is: unitary, elastic or inelastic.

Suppose that consumption function is given by = 80 + 8

a) Calculate the value of Marginal Propensity to Consume (MPC) and Marginal Propensity to Save (MPS) when =200

b) Give an interpretation on result in (a).