Can the lenght of 6cm,13cm and 7cm form a triangle

What is the sum of these mixed numbers 2 1/8 + 4 3/8

Yosef can eat 21 jamuns while rose can eat just 15 . complete the blank. yosef can eat % more jamuns than rose.

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