Julius has three times as many stamps in his collection as his friends Liam and Mario combined. Liam has 10 stamps
in his collection. Julius has 87 stamps in his collection.
How many stamps does Mario have in his collection?

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