
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
$\textbf{Elena's Vintage Postcard Collection}$

Elena organizes her postcard collection by region and by the decade in which they were issued. The prices she paid for them at an antique store were: Asia and Africa, $7$ cents each, Europe $5$ cents each, and North America $6$ cents each. (Asia and Africa are grouped under Eastern Hemisphere, Europe and North America are Western Hemisphere.)

In her collection, the distribution of postcards by decade and by region for the 1950s through the 1980s is as follows:

| Decade     | Asia | Africa | Europe | North America |
|------------|------|--------|--------|---------------|
| 1950s      | 5    | 3      | 7      | 4             |
| 1960s      | 8    | 6      | 5      | 10            |
| 1970s      | 14   | 11     | 8      | 12            |
| 1980s      | 9    | 7      | 6      | 15            |

How much did her postcards from the Eastern Hemisphere issued before the 1970s cost her?

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