At school, the maximum numer of students that can be in the classroom is 27. If there 20 students signed up for the geometry class, how many more students can join the class?

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document