How old is Ferris Bueller's sister?

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October 19, 2010 5:02AM

Let's look at what we know:

1) She's Ferris' younger sister.

2) Ferris is a senior.

3) Seniors are usually 18 or 19.

4) She has a car.

5) The legal driving age in Illinois is 16.

6) When arrested, she's treated as a juvenile.

SO: Ferris' sister is at least 16, she can't drive if she's not 16. She can't be more than 18 and be Ferris' younger sister. When arrested she's treated like a juvenile, so she can't be 18.

ANSWER: 16-17

The answer above is incorrect. If you read the script which is posted online [], Jeanie is described as the older sister.