question for economics

4) Al only consumes two goods, food (x) and clothes (x). Suppose that at an income of $1,000 he consumes 20 units of x, and 50 units of x2. When his income increases to $1,100, he consumes 15 units of x, and spends the rest of his money on x2. There is no change in the price of the goods. a) What is Al's income elasticity for food (x,)? b) What type of good are clothes (normal, neutral, or inferior)? How do you know