Find the mean of the data in the dot plot below. Make sure to show your work and explain he steps you took in solving the problem using the words "first," "next," and "last."
​

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?