
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
Two girls, $C$ and $D$, begin cycling from City X towards City Y, which is $100$ miles away. $C$ cycles $6$ mph slower than $D$. After reaching City Y, $D$ immediately turns back and eventually meets $C$ who has also turned back $20$ miles before reaching City Y and then met $D$ $15$ miles away from City Y. Find the speed of $C$.
A) 25 mph
B) 28.5 mph
C) 30 mph
D) 32 mph

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