a person saves rs.100 in beginning and then every month he saves rs.50 more than the previous month. After how many months he saves rs.257500

What are “like terms”? why can we only add like terms?

Need on this one asap im almost done with this subject

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?