To determine the fraction of her essay that Zoe wrote each minute, we need to find out how much of the essay she wrote in one minute, given that she wrote three-fifths of the essay in 30 minutes.
To find the fraction she wrote each minute, we divide the total fraction she wrote (three-fifths) by the time it took (30 minutes).
This can be expressed as:
\[ \text{Fraction written per minute} = \frac{3/5}{30} \]
This is equivalent to:
\[ \frac{3/5}{30} = \frac{3}{5} \times \frac{1}{30} = \frac{3}{150} = \frac{1}{50} \]
Thus, the correct expression that can be used to determine the fraction of her essay she wrote each minute is:
Three-fifths divided by 30.