Question

Geometry help:

Shelly, Jess, and Andrea are all working at an amusement park for the summer. The manager finds out that one of them left the key in the door to the security office. When he asked them who did it, they replied:

Shelly: Jess did it.
Jess: I didn’t do it.
Andrea: Jess did not do it.

The manager believed Jess. Use an indirect proof to show that Jess did not leave the key in the security office door.

Hint: Begin by assuming Jess did leave the key in the door.

Answer 1

This is what I have so far, if anyone could tell me if I'm wrong or if I'm missing something, that'd be great.

Answer 2

Step 1: Jess did leave the key in the door.
Step 2: Andrea agrees the Jess didn't leave the key in the security office door.
Step 3: Jess did not leave the key in the security office door.

Answer 3

Got it, nvm guys. For anyone else, my final answer was:

Step 1: Assume Jess did leave the key in the door.
Step 2: Andrea agrees the Jess didn't leave the key in the security office door.
Step 3: Since two of the three statements are true, this proves that the original statement is false, concluding to: Jess did not leave the key in the security office door.