Line segments ab and cd are both part of the same non–vertical line, and the slope of line segment ab is 4. using similar triangles, what can you show the slope of line segment cd to be?

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?