Given:
If Sue gets asked for homecoming, then she will go to the mall. If she goes to the mall, then she will buy a dress.
Let,
a: Sue gets asked for homecoming
b: she will go to the mall
c: she will buy a dress.
The law of syllogism states that,
So, by using the law of syllogism we get,
If Sue gets asked for homecoming then she will buy a dress.