On Monday, 449 students went on a trip to the zoo. All 9 buses were filled and 8 students had to travel in cars. How many students were on each bus?

To find out how many students were on each bus, we first need to determine how many students traveled by bus.

If there were 449 students in total and 8 students traveled by car, then the number of students who rode the buses is:

\[ 449 - 8 = 441 \]

Next, we know that there were 9 buses filled with students. To find out how many students were on each bus, we divide the total number of students who traveled by bus by the number of buses:

\[ \text{Number of students on each bus} = \frac{441}{9} \]

Calculating this gives us:

\[ \frac{441}{9} = 49 \]

Therefore, each bus had 49 students on it.