Please give an example

Principle 1: A dollar earned today is worth more than a dollar earned in the future. A fundamental concept in engineering economics is that money has a time value associated with it (Figure 1.3). Because we can earn interest on money received today, it is better to receive money earlier than later. This concept will be the basic foundation for all engineering project evaluation. If you receive $100 now, you can invest it and have more money available six months from now $100 $100 Earning opportunity Today Six months later Figure 1.3 Time value of money