Aaron is making 3 1/2 batches of brownies. each batch takes 2 1/2 cups of flour. how much flour will john need for the brownies?

Becca wants to mix fruit juice and soda to make a punch. she can buy fruit juice for $3 a gallon and soda for $4 a gallon. if she wants to make 28 gallons of punch at a cost of $3.25 a gallon, how many gallons of fruit juice and how many gallons of soda should she buy?