
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Some students are running a fundraiser by organizing a charity show. Initially, $50\%$ of the group are girls. After the event starts, three girls leave and four boys join, and then $40\%$ of the group are girls. How many girls were initially in the group?
A) 15  
B) 16  
C) 17  
D) 18  
E) 19

Present the answer in LaTex format: \boxed{Your answer}
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