What is the algebraic expression for \"the difference between seven times a number and three times that number\"?

Empty box + box + empty box fill in the box is equal to 30 how

Jermaine has t subway tokens. karen has 4 more subway tokens than jermaine. raul has 5 fewer subway tokens than jermaine. which expression represents the ratio of karen's tokens to raul's tokens

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?