
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
A shoe store offers two promotions. Promotion A says, "Buy one pair of shoes, get the second pair for half the price." Promotion B says, "Buy one pair of shoes, get $\$20$ off the second pair." Mark wants to buy two pairs of shoes that cost $\$50$ each. He can only use one of the promotions, A or B. Mark decides to use the promotion that will save him the most money. How many dollars does Mark save by picking one promotion over the other?

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