The nut house sells pecans worth per pound and cashews worth $8 per pound. how many pounds of pecans and how many pounds of cashews must be mixed to form 24 lb of a nut mixture worth $ per pound?

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