
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
In 1990, the average cost of a particular textbook was $75$, and in 2010, the average cost had decreased to $60$. Find the approximate percent decrease in the cost of the textbook.
A) 10%
B) 15%
C) 20%
D) 25%
E) 30%

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