Jon has to pay $7.50 admission for the skating rink and $1.50 per hour to rent roller blades how much would it cost to skate for 3 hours

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?

Can someone me out here and the tell me the greatest common factor

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?