The u. s. department of transportation estimates that citizens own more than 12,720,000 registered boats. which shows this number rounded to the nearest ten million? a. 10,000,000 b. 12,000,000 c. 13,000,000 d. 20,000,000

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