I had a disagreement with my parents on of I should buy a used car or spend more money to buy a new car. They wanted me to buy a used car because it is cheaper. I wanted to buy a new car because it would last me longer. I am not sure now if I should buy a car for the quality or for the price. I do not have a large amount of money to spend on a new car, but I need a car that will last a long time.
B: get a car that is cheap
D: buy a used car
A: buy a car that is cheap and will last a long time
| D-D': | Assumption(s) | Injection(s) |
| I cannot buy both a used car and a new car | I can buy a car that has only been lightly used |
C: get a car that will last a long time
D': buy a new car
In order to buy a car that is cheap and will last a long time I must get a car that is cheap and in order to get a car that is cheap I must buy a used car. But, in order to buy a car that is cheap and will last a long time I must also get a car that will last a long time and in order to get a car that will last a long time I must buy a new car. I can't both buy a used car and buy a new car.
| Relation | Assumption(s) | Injection(s) |
| D-D' | I cannot buy both a used car and a new car | I can buy a car that has only been lightly used |
| B-D | used cars cost less than new cars | not all new cars cost more than used cars |
| C-D' | new cars last longer than old cars | Some old cars can last a long time if kept in good condition |
| A-B | I do not have a large amount of money | Not all cars that are cheap last a long time |
| A-C | I will need to use the car for a long time | Not all cars that last a long time are cheap |