What does 5.9E4 mean?

I’m really confused and need your assist me with this question i’ve never been taught

Table of values relation g values x, y 2,2 /3,5 /4,9 /5,13 which ordered pair is in g inverse? a(-2,2) b(-3,-5) c)4,9) d( 13,5)

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?