Answer:  The required ratio in simplest form is 3:5 or 5 :3.
Explanation:
We know that the ratio of A to be is defined as A:B , which can also be written in fraction as 
 .
 .
Here , we need to find the ratio of 3 gallons to 5 tons which will be 
 or 3:5.
 or 3:5.
Or in other case , the ratio of 5 tons to 3 gallons will be 
 or 5:3.
 or 5:3.
Also , 3 and 5 are co-prime ( i.e. they do not have any common factor).
Thus the required ratio in simplest form is 3:5 or 5 :3.