To determine how many parents will go on the museum field trip, we first need to find the ratio of parents to students from the aquarium field trip.
From the aquarium field trip:
- There were 15 parents and 75 students.
The ratio of parents to students is: \[ \text{Ratio} = \frac{\text{Number of Parents}}{\text{Number of Students}} = \frac{15}{75} \]
We can simplify this ratio: \[ \frac{15}{75} = \frac{1}{5} \]
This means that for every 1 parent, there are 5 students.
Now, let's apply this ratio to the museum field trip where there are 25 students going. To find the number of parents needed for these 25 students, we use the ratio of 1 parent per 5 students.
Let \( x \) be the number of parents needed for 25 students. According to the ratio: \[ \frac{x}{25} = \frac{1}{5} \]
To solve for \( x \), we can cross-multiply: \[ x \cdot 5 = 1 \cdot 25 \] \[ 5x = 25 \]
Now, divide both sides by 5: \[ x = \frac{25}{5} = 5 \]
Thus, the number of parents that will go on the museum field trip is \( \boxed{5} \).