Answer: 
Ruben bought 19 pounds of sugar for $9.So 2.1 pounds of sugar he got per dollar. 
Solution: 
Given Data: 
Ruben bought 19 pounds of sugar for $9. 
We need to find that how many pounds of sugar he got per dollar. 
Let’s solve using the given Data. 
Step 1: 
19 pounds for 9 dollars. 
To get the per pound value divide given data in pounds by dollar value. 

Step 2: 
On dividing the above value we get the value as 2.1 
 = 2.1
 = 2.1 
Step 3: 
By Step 2 we got the number of pounds which he get sugar per dollar. 
Result: 
He got 2.1 pounds of sugar per dollar.