Answer:
Carmen can make  full servings.
 full servings.
Step-by-step explanation:
 Given : Carmen mixes  cups of water with
 cups of water with  cups of juice to make punch.
  cups of juice to make punch.
Total quantity of punch Carmen made = total cup of water + cup of juice she mixes 
Total quantity of punch Carmen made = 
Solving , we get,
Total quantity of punch Carmen made = 
taking LCM(2,8) = 8 , we get,
Total quantity of punch Carmen made = 
Also, given She pours  cup servings of punch.
 cup servings of punch.
Thus,  cup of mixture makes 1 serving cup.
 cup of mixture makes 1 serving cup.
Using unitary method, 
In unitary method we first find the value of a single quantity and then multiply it with the desired quantity.
1 cup of mixture makes  serving cup.
 serving cup.
 cup makes =
 cup makes = 
 cup makes =
 cup makes = 
Thus, She can make  full servings.
 full servings.