# Microeconomics homework question-proving that a good is normal

1. May 30, 2012

### Mike s

Hey,
I need help with the following question in microeconomics:
A consumer lives in a world of two goods: computers and money. Let x be the number of computers,the consumer can buy.
$x\epsilon [0,1,2,3]$
The consumer has the following preference relation: If the consumer has money and no computers, he is willing to spend at most half of his money on buying a single computer. If the consumer has 1 computer, he is willing to spend 1/3 of his money on buying a second computer. If the consumer has 2 computers, he is willing to spend 1/4 of his money on buying a third computer.

A. Explain why $(0,M)$~$(1,\frac{M}{2})$~$(2,\frac{M}{3})$~$(3,\frac{M}{4})$

B.Explain why the consumer's preference relation can be represented the following utility function $U(x,M)=(x+1)M$.

C.Prove that computer is not an inferior good

I have managed to solve A,B , however I need help in C.