Answer: 4 gallons require 5 5/39 spoons of syrup
Explanation:
Given it takes 3 2/6 spoons to make 2 3/5 gallons of chocolate milk
i.e. 20/6 spoons make up 13/5 gallons of milk
⇒1 gallon require 20/6/13/5 spoons of milk
⇒ 20 x 5/6 x 13 spoons of milk
⇒ 100/78 spoons of milk
Therefore 4 gallons require 4 x 100/78 spoons
⇒ 400/78 spoons
⇒ 200/39 spoons
⇒ 5 5/39 spoons