
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
Reading material: Yuan Longping, the recipient of the "Republic Medal" and known as the "Father of Hybrid Rice," successfully developed hybrid rice, which has a yield per acre that is twice that of ordinary rice. There are two experimental fields, field $A$ planted with hybrid rice and field $B$ planted with ordinary rice. Field $A$ has $4$ fewer acres than field $B$.  
$(1)$ Field $A$ harvested $9600$ kilograms of rice, and field $B$ harvested $7200$ kilograms of rice. Find the yield per acre of ordinary rice and hybrid rice, respectively.  
$(2)$ In order to increase the yield, it is planned to convert a part of field $B$ planted with ordinary rice to hybrid rice next year, so that the total yield is not less than $17700$ kilograms. How many acres of field $B$ should be converted to hybrid rice at least?

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