Answer: 1.5 acres.
Step-by-step explanation:
According to the given question , we have
The total area of field the farmer needed to plow = 6-acre
The part of field with which she starts plowing =
(in fraction)
Now, the part of field (in acres) with which she starts plowing = Part in fraction x Total area.

Hence, the farmer plows 1.5 acres.