For questions 9 and 10 , express each rate as a unit rate. 9] 85.5 meters in 45 seconds 10] 243 students to 9 classrooms

To get the unit rate for both of the questions, you'll be needing to divide to get one individual unit rate.
Example:
Q.9: We need to figure out how many metres are in one single metre. You simply do this by dividing 85.5 by 45.

85.5 / 45 = 1.9.
This means that the unit rate was 1.9 per second.

Q.10: Similar to the first example except now you have to figure out how many students are in one classroom. You find this out by taking 243 and dividing it by 9.

243 / 9 = 27
This means that the unit rate is 27 students per classroom.

Sorry if this sounds a bit confusing.