Answer:
 or 
 wheels of cheese is left for Wednesday.
Explanation:
A deli ordered 
 or 
 wheels of cheese.
Over the weekend 
 or 
 wheels of cheese we're sold.
On Tuesday 
 or 
 of cheese we're sold.
Total cheese sold in these days = 

= 
 = 
 
Now cheese left for Wednesday = 

= 
 = 
 
Hence, 
 or 
 wheels of cheese is left for Wednesday.