Answer:
(35/6) spoons of syrup would be needed.
Explanation:
First, we make the conversion of the measures from mixed numbers to fractions.
3 1/2 spoons

3 3/5 gallons

Now, we make a rule of three.
For 7/2 spoons, we need 18/5 gallons.
How many spoons for 6 gallons?
7/2 spoons - 18/5 gallons
x spoons - 6 gallons.
Applying cross multiplication:





Now, we simplify by 3;

(35/6) spoons of syrup would be needed.