Ten princiles of ecanomic

Principle 2:The cost of something is what you give up to get it

This principle is based on the above rule, “ There ain’t no such things as a free lunch”, or “Beauty requires sacrifice” If we want to achieve goal, we have to spend our time, money ,or mental labor. For example if I want to open a car factory, I need a lot of knowledge and experience ,a lot of time and money.

Principle 3:rational people think at the margin

Rational people decision making by comparing marginal benefits and marginal cost.they also know very well what to spend their money and time on ,to whom a where.