Can someone helpp wit htis

John can eat 10 cookies in 1/2 hr how many cookies can he eat in 45 minutes make a proportion and solve

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?