Let me work through this step-by-step.

Sally has 3 brothers.

Each of Sally's brothers has 2 sisters.

Since Sally is a girl, she is one of the sisters that each brother has.

If each brother has 2 sisters total, and Sally is one of them, then there must be 1 other sister besides Sally.

Therefore, Sally has 1 sister.

Let
• S = number of sisters in the family (girls)
• B = number of brothers in the family (boys)

Given

1. Sally has 3 brothers ⇒ B = 3.
2. Each brother has 2 sisters ⇒ every boy sees exactly 2 girls in the sibling group.
   Therefore S = 2.

Since Sally herself is one of those 2 sisters, the number of sisters Sally has (other than herself) is

2 – 1 = 1.

Sally has 1 sister.

Here are 5 jokes:

1. Why don't scientists trust atoms? Because they make up everything!

2. What do you call a bear with no teeth? A gummy bear!

3. Why did the scarecrow win an award? He was outstanding in his field!

4. What do you call a fake noodle? An impasta!

5. Why don't eggs tell jokes? They'd crack each other up!

All 5 jokes are unique - each one has a different setup and punchline with no repeats.

Here are five jokes:

1. Why did the scarecrow win an award? Because he was outstanding in his field.
2. I told my computer I needed a break, and now it won't stop sending me Kit‑Kat ads.
3. Parallel lines have so much in common—it's a shame they'll never meet.
4. I started a band called 1023 MB. We still haven't gotten a gig.
5. Why don't scientists trust atoms? Because they make up everything.

How many of these jokes are unique?
All five are distinct from one another, so the answer is 5.