To solve the problem, let's define the number of students who choose band as \( b \) and the number of students who choose choir as \( c \).
From the problem, we know:
- The total number of students is 250.
- There are four times as many seats in choir as there are in band, which means \( c = 4b \).
Now, we can set up the equation based on the total number of students:
\[ b + c = 250 \]
Substituting the expression for \( c \):
\[ b + 4b = 250 \]
Now, combine the terms:
\[ 5b = 250 \]
To find \( b \), divide both sides by 5:
\[ b = \frac{250}{5} = 50 \]
Thus, the number of students who can choose band is \( \boxed{50} \).