Nstands for a whole number 2n is greater than 30, so what does n stand for

Which of those sequences is a geometric sequence

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning

Which of the following is the result of expanding the series