This question is based on least common multiple method.
As given in the question,
Aunts are taking pictures in group of = 5
Uncles are taking pictures in group of = 10
So we have been asked what is the minimum number of aunts Sana have.
As we have been given that the number of aunts and uncles is equal so to find the minimum number of aunts we will apply the least common multiple method.
So we get LCM of 5,10 as 10
Hence there are minimum 10 aunts.
Answer:
The result is 19
Step-by-step explanation:

Step 1: Parenthesizing (5-2)=3

Step 2: Exponentiation 

Step 3: Multiplication and division 3x4=12 and 6/3=2

Step 4: Addition and subtraction 9+12=21, and 21-2=19
21-2
19
The operations are ordered from highest to lowest in the order:
1. Parenthesizing,
2. Factorial,
3. Exponentiation,
4. Multiplication and division,
5. Addition and subtraction.
Hope this helps!