1)when would it be very useful to know the fact that the product of a number and it's reciprocal is 1 (hint: equations)?

2)what is a common misconception that a student might have when trying to explain the definition of reciprocal?

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?